UNIT#01 FORCE AND MOTION Flashcards
(350 cards)
1
Q
A cyclist moves along a circular path of a radius of 70m if he completes one round in 11 sec.
Calculate the total length of the path:
A
440m
(Total Length of the hemisphere: 2πr)
2
Q
A body is projected horizontally from the top of a cliff with a velocity of 9.8 m/s. What time elapses before horizontal and vertical velocities become equal?
A
1 sec
(➡Horizontal Component: vx=9.8 ms-1
➡Vertical Component: vy=gt
3
Q
Two bullets are fired simultaneously, horizontally and at different speeds from the same place. Which bullet will hit the ground first?
A
Both will reach simultaneously
(T=√2h/g)
➡Mass does not have any role
4
Q
A body is moving along a straight path. What will happen to the body in the absence of an external field;
A
It will move at the same speed along the same straight path
(Newton’s First Law)
5
Q
A person is standing on a bus. When the bus starts moving forward suddenly:
A
The person moves backwards
(Due to inertia)
6
Q
A ship of mass 3x10^7 kg initially at rest is pulled by a force of 5x10^4 N through a distance of 3m. Assuming that the resistance due to water is negligible., the speed of the ship is;
A
0.1 m/s
(v=√2aS)
(a=F/m)
7
Q
Which of the following is an example of inelastic collision:
➡If there is loss of Kinetic Energy
A
The collision between two vehicles
8
Q
Mud thrown on a wall and sticking to it is an example for:
A
Perfectly inelastic collision
(if two bodies stick together and move with common velocity, then perfectly inelastic collision)
9
Q
A body moves 6m North, 8m East and 10m vertically upwards, what is its resultant displacement from the initial position;
A
10√2m
10
Q
The instantaneous acceleration is the limit of average acceleration is Δt➡0 is given by
A
The formula of instantaneous acceleration
11
Q
If an object is moving with a constant velocity of 20ms-1 towards the north then its acceleration will be;
A
0 ms-2
(as it is moving with constant velocity)
12
Q
The retardation is defined as;
A
Decrease in velocity per unit time
13
Q
Consider the acceleration, velocity and displacement of a tennis ball as it falls to the ground and bounces back. Directions of which these changes in the process:
A
➡Displacement
➡Velocity
14
Q
A particle foes from from x= -2m, y=3m, z=1m to x=3m, y=-1m, z=4m. Its displacement is;
A
(5m)i - (4m)j + (3m)k
(Displacement= B-A)
15
Q
The length of the path of a particle is equal to the magnitude of the displacement of that particle. The shape of the path possible
A
Straight Line
16
Q
The shortest distance between two points is called
A
Displacement
17
Q
Two cars moving in opposite directions with speed v. What is the magnitude of their relative velocity?
A
2v
(For bodies moving in opposite directions relative velocities add up)
18
Q
A body can have constant velocity it follows;
A
Rectilinear motion
18
Q
A man in a car is moving with a velocity of 36 km/hr. His speed with respect to the car is;
A
Zero
(man is at rest)
19
Q
A man leaves his house for a cycle ride. He comes back to his house half an hour after covering a distance of one km. What is his average velocity for the ride;
A
5ms-1
20
Q
If the slope of a velocity-time graph gradually decreased, the body is said to be moving with
A
Positive acceleration
21
Q
If the force acting on a body is doubled, then acceleration becomes:
A
Doubled
22
Q
When the force of 1N is applied on a body of mass of 100g then the acceleration would be;
A
10 ms-2
23
Q
A mass of 10kg moves with an acceleration of 10ms-2, then force on it is;
A
100N
24
Which law of motion defines force?
1st Law
25
A force of 12N gives an object an acceleration of 4 m/s2. The force required to give it an acceleration of 10ms-2 is:
30N
26
When a force of 4N acts on a mass of 2kg for a time of 2 sex, what is the rate of change in momentum
4 kgms-2
27
Which is a statement of the principle of conservation of momentum?
The total momentum of a system of interacting bodies remains constant, providing no external force acts
28
The average force necessary to stop a hammer with 25 Ns momentum in 0.05 sec expressed in 'N' is:
500
29
In which of the following cases forces may not require to keep them;
The momentum of a particle remains constant
30
A force of 6 N acts on a mass of 1kg which acquires a velocity of 30 ms-1. The time for which the force acts as;
5 sec
31
A force of 100 Dynes acts on a mass of 5 g for 10 sec. The velocity produced is:
200 cm/sec
32
A gun after firing recoils due to;
Conservation of momentum
33
A player takes 0.1 sec in catching a ball of mass 150 g moving with a velocity of 20 m/s. The force imparted by the ball on the hands of the player is;
30 N
34
a ball of mass 2kg travelling at 8ms-1 strikes a ball of mass 4kg travelling at 2ms-1. Both balls are moving along the same straight line.
After the collision, both balls move at the same velocity v. What is the magnitude of the velocity v?
4 ms-1
35
Two similar spheres, each of mass m and travelling with speed v, are moving towards each other
The spheres have a head-on elastic collision. Which statement is correct
The total kinetic energy after impact is mv2
36
Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together.
What is the speed of the trucks after the collision?
v/4
37
The collision between the two bodies is elastic if the bodies are:
➡Solid
➡Hard
38
When a very heavy ball 'B1' collides with a stationary target 'B2' of negligible mass, after the collision the final velocity of ball 'B2' will;
Become doubled as compared to B1
39
A shell explodes into four equal parts. Which one of the following is conserved?
Momentum
40
A handball is tossed vertically upward with a velocity of 19.6 meters per second. Approximately how high will it rise?
20m
41
Which shows the correct relation between time of flight T and maximum height H?
H=gT2/8
42
At the maximum height on the trajectory which projectile becomes zero
Vertical Velocity
43
Time taken by a projectile to reach maximum height is t=
2vi sinΘ/g
44
Two projectiles are projected at an angle of 20° and 70° with the same velocity one has a longer range
Both have the same range
45
The path followed by a projectile is known as its:
Trajectory
46
A projectile is fired horizontally with an initial speed of 20 m/s. Its horizontal speed 3s
20 m/s
(Horizontal component of speed remains constant)
47
For which of the following angles range is maximum?
43°
48
A bullet is fired horizontally from a rifle at a distant target. Ignoring the effect of air resistance, what is the horizontal and vertical acceleration of the bullet?
Horizontal➡0
Vertical➡9.8 ms-2
49
Under what condition an object will have zero displacement but non-zero distance
Circular Motion
50
What is the acceleration of a projectile relative to another projectile:
0
51
If the flock of birds is flying, the total momentum will be zero if;
Very tired and coming down to rest
52
The slope of the distance-time graph will always be;
Positive
53
At what angle of projection of a projectile the range becomes half of its maximum value;
15°
54
If we drop an object, its initial velocity is zero. How far will fall in time 't'?
4.9 t2
55
The newton-second is a unit of;
➡Impulse
➡Momentum
56
The accelerating frame of reference which has constant acceleration is;
free falling body on earth
57
Vertical velocity vs time graph for a projectile motion
Varies linearly
58
Pseudo forces arise in;
The accelerating frame of reference
59
The magnitude of displacement is;
Straight line distance between the initial and final position
60
A car travels 30m towards the east, then it takes to turn and travels 40 m towards the west, its average velocity after 60 sec.
1/5 ms-1
61
Displacement of the sun with respect to earth is;
r
62
Instantaneous velocity is;
➡Positive
➡Negative
63
If the displacement=15 m and time=10 sec, the average velocity is;
1.5 m/s
64
A decrease in velocity per unit of time is called;
Acceleration
65
For a linear relationship between displacement and time, we get a d-t graph:
Straight Line passing through the origin
66
An object is moving with constant speed, which of the following is true?
Distance is greater than displacement
67
A stone is projected from the ground with a velocity of 25 m/s. 2 seconds later it just clears the wall 5m high. Then the angle of projection of the stone and the greatest height reached are:
➡60°
➡8.7m
68
Acceleration of moving car when brakes are applied;
Negative
69
The slope of the distance-time graph will always be;
Positive
70
The slope of the velocity-time graph represents
Acceleration
71
An object is accelerating:
When its speed or direction is changing
72
What is the slope of a straight line graph of position vs time?
Displacement
73
If the velocity versus time graph of an object is a horizontal line, the object is:
Moving with zero acceleration
74
The acceleration of a moving object can be found from;
The slope of the velocity-time graph
75
The coefficient of restitution for a perfectly elastic collision is;
1
76
Walking is possible on the account of;
Newton's Third Law of Motion
77
The coefficient of restitution for a perfectly inelastic collision is;
Infinity
78
When two bodies stick together after the collision, the collision is said to:
Perfectly Inelastic collision
79
What is the accelerating force on the Diwali rocket if it ejects 0.05 kg of gases per second at a velocity of 400 m/s?
20N
80
If the mass is 2kg and the velocity is 35 m/s, then the momentum is:
70 kg m/s
81
If force is doubled by keeping mass constant then the acceleration would be;
Halved
82
Newton's third law is derived from;
Newton's 2nd Law
83
Force exerted by the wall on the water will be;
F=mv/t
84
If a car and Truck move with the same velocity and we applied the same force on both which body comes to rest first
Car
85
If the maximum horizontal range is 40m, then what will be the height attained by the projectile;
800m
(RtanΘ=4H)
86
According to the 2nd Law of motion, which is correct?
Acceleration is not related to mass
87
Car weight of 000 has a velocity of 50 km per hour. If a mass of 250 is placed in this then velocity becomes;
100
88
The dimension of momentum is the same as;
Impulse
89
Displacement time graph slope gives us a unit of:
m/sec
90
Kgm/s2 is equal to;
Force
91
In elastic collision which of the following is constant
Momentum
92
Kinetic friction is always than static friction:
Less
93
Momentum is the product of:
➡Mass
➡Velocity
94
The momentum of particle changes when;
➡Energy is changed
➡Force is applied
95
The speed of an object in a particular direction is called:
Velocity
96
The acceleration time graph for projectile motion will be;
Straight Line
97
A mass accelerates uniformly when the resultant force acting on it is:
Constant but not zero
98
Which law of motion defines force?
1st Law
99
If the velocity-time graph is parallel to the y-axis then acceleration
0
100
The body moves from rest with a constant acceleration of 5. It instantaneous speed at the end of 10 seconds is:
50
101
A train of length 200m is crossing a bridge 400m in length at speed of 36km/h. What is the total time by train to cross the bridge
60sec
102
A hunter aiming a bird in a tree should aim;
a little above the
103
The horizontal component of a bouncing ball is;
unaffected by gravity
104
A ball is dropped from a height of 10m. The ball is embedded in sand 1m and stops, then,
Only momentum remains conserved
105
Which of the following is momentum closely related to;
Impulse
106
An object will possess uniform motion as long as the;
the resultant force acting on it is zero
107
In an elastic collision of two particles, the following is conserved
The total kinetic energy of both the particles
108
The displacement is a;
Vector quantity
109
Projectile motion has ___ acceleration at each point of the trajectory
Constant
110
A projectile is launched with vertical kinetic energy K at angle Θ, then its variation with vertical displacement Y
Linear
111
Projectile when launched at 90 degrees with respect to horizontal then its trajectory is;
Linear
112
In which situation, distance is three times its displacement?
The object moves 20m towards east and 10m towards south
113
SI unit of acceleration is:
m/s2
114
If we are standing in a bus and when conductors apply a brake then we feel;
the pseudo force pushes backwards
115
Horizontal velocity vs time graph for a projectile motion is;
is constant
116
Acceleration of the object which starts rest to reach 20 m/s in 10 sec is;
2 m/s2
117
If a projectile is launched with 3m/s velocity at a 60-degree angle then at the highest point its horizontal velocity is;
1.5 m/s
118
If velocity varies with time in a quadratic manner, then acceleration:
Linearly varying
119
Vector is a quantity which:
follows the rule of vector addition
120
The amgnitude of the dispalement is:
straight line distance between the initial position and the final position of the body
121
The net force acting in an inertial frame is;
zero
122
An object moves 20m in 5 sec. What is the gradient of the displacement-time graph?
4
123
The circular motion of a particle while attached to a string centripetal acceleration is provided by:
Tension in the string
124
Passengers sitting in a stationary car experience a jerk when the car suddenly starts. This is due to:
inertia of rest
125
For a linear relationship between displacement and time we get a d-t graph as;
a straight line passing through the origin
126
At every point of the trajectory of the projectile which of the following quantities is always zero
Horizontal acceleration
127
Which unit is used in the measurement of displacement?
m/s
128
Acceleration of a moving car when brakes are applied is:
Negative
129
A horizontal line in displacement-time graph represents___
Body at rest
130
A motion with uniform negative acceleration can be represented on the displacement-time graph by:
a curve line with decreasing gradient
131
When an object moves in a straight line then;
its displacement is equal to the distance
132
If one body is at rest then if we try to move it then it will resist by:
Inertia of rest
133
If the velocity varies linearly with time then acceleration is called:
Uniform
134
Mass m1 has a velocity of 0m/s and mass m2 has a velocity of 5 m/s. Mass m1>m2.
Which one has larger inertia?
m1
135
Consider a car is travelling for one hour. In which of the following causes the average velocity is zero?
A car travels 30km due west, then turns around and travels 30km due east
136
Newton's second law states that the rate of change of ___ is equal to external force:
Momentum
137
The velocity of an object changes from 20m/sec to 50 m/sec in 5 sec. What is the acceleration of the object?
6 m/s2
138
For a car which applies brakes from 10m/sec to stop the car in 10 sec its acceleration is:
-1 m/s2
139
Instantaneous velocity is defined as;
dx/dt
140
Which of the given motions is a type of 2D motion:
➡Circular
➡Pendulum Motion
➡Projectile motion
141
If an object moves with constant velocity then its acceleration is;
zero
142
When a stone is thrown horizontally with 2 m/sec from a building of height of 5m then just before hitting the ground its acceleration is;
9.8 m/sec2
143
The displacement between A and B is defined as;
change in position of an object from a to b
144
If a car starts from rest and reaches 20 m/s velocities in 10m distance then acceleration is:
20 m/s2
145
The distance and displacement can be equal if:
an object moves in a straight line
146
Instantaneous velocity is defined as;
Instant time
147
Consider a car is travelling for one hour. In which of the following cases the average velocity is zero?
a car travels 30km due west, then turns around and travels 30km due east
148
If an object moves with constant velocity then its acceleration is:
Zero
149
Acceleration of moving train when it starts its motion is;
Positive
150
If the velocity of the particle is varying linearly with time then the shape of the d-t curve would be;
Linear
151
If a car is travelling eastward and slowing down, what is the direction of acceleration:
Westward
152
Vertical velocity vs time graph for a projectile motion:
Varies Linearly
153
Consider a car is travelling or one hour. Which one of the following cases has the greatest average velocity in the east direction?
A car travels 70km due east
154
The displacement has;
➡Magnitude
➡Direction
155
An object is moving at a constant speed, which of the following is always true:
➡Distance is greater than displacement❌
➡Distance is lesser than displacement❌
➡Distance is equal to displacement❌
156
The projectile motion of objects on earth is always:
Parabolic
157
When an object moves on a circular path, then:
Its displacement changes due to change in direction of motion
158
1 light year distance is;
Distance travelled by light in one year
159
Displacement is a:
Vector
160
The average speed of an object after a completing circle of 5m radius in 5 seconds:
2π
161
Centripetal acceleration always acts ___ the centre.
Towards
162
Pseudo forces arise in:
the accelerating frame of reference
163
If we are moving with a constant velocity frame then the inertial state is the same as;
Rest Frame
164
A car travels 30 m towards the east, then it takes a turn and travels 40 m towards north. It takes 50 seconds. It average velocity is;
1 m/s
165
The average velocity of an object after completing a circle of 5m radius in 5 seconds;
Zero
166
If an object is speeding up:
➡Velocity is negative
➡Acceleration is positive
167
Acceleration describes how;
the speed and direction of motion are changing
168
If we apply 100N fore on a 10kg box then its acceleration is;
10 m/s2
169
Consider a displacement-time graph of an object moving along the x-axis. Then negative gradient of the graph becomes
Velocity in Negative x -direction
170
Speed is a:
Scalar
171
Displacement of an object in moving around a complete circle is;
Zero
172
Velocity is a:
Vector
173
A straight-moving bus takes a sharp right turn. What will happen to the passengers sitting on the bus?
They will tilt leftwards
174
People sitting in a moving bus experience a jerk when the bus stops. This is due to;
Inertia of motion
175
We can calculate the velocity of an object from a displacement-time graph by;
Finding the gradient of the displacement-time graph
176
A motion with increasing velocity can be represented on a displacement-time graph by:
a curve line with increasing gradient
177
The acceleration of a moving object can be defined as:
rate of change in velocity
178
Acceleration of an object is defined as the rate of change of;
Velocity
179
At the highest point of the trajectory which of the following quantities is zero:
Vertical Velocity
180
Rockets use thrust forces which produce;
Variable acceleration
181
Which of the following vector is perpendicular to the vector A = 2i + 3j +4k
i + 2j - 2k
182
The rate of change in displacement is known as;
Velocity
183
Acceleration is always ___ for a freely falling body
Positive
184
The value of acceleration due to gravity on the moon is ___ of earth
1 / 6th
185
Inertia refers to the tendency of an object to;
remain in the same state as previous
186
Displacement and distance moved by an object in a straight path are:
Same
187
Acceleration of particle at any moment from a-t graph we calculate is called ___ acceleration.
Instantaneous
188
Average velocity is defined as;
Displacement/Time
189
Acceleration of a rolling object is zero at ___ point of hill;
Highest
190
Acceleration due to gravity near the earth is:
Uniform
191
Newton's first law is applicable only in:
Inertial Frame
192
The value of acceleration due to gravity on earth is:
9.8 m/s2
193
Projectile motion is not dependent on the ____ of particle,
Mass
194
Acceleration of earth around the sun in its orbit is always.
Tangential
195
If a squash ball comes back to its starting point after bouncing off the wall several times, then;
Its total displacement is zero and so also is its average velocity
196
An object moves 20m towards the east and then 10m towards the west, in 5 sec. What are its average velocity and average speed?
➡Speed= 6m/s
➡Velocity= 2 m/s
197
The acceleration is a:
Vector Quantity
198
If the velocity of an object is increasing with time then acceleration is;
Positive
199
If the displacement-time graph is a curve, which of the following is correct:
➡Area under graph represents velocity❌
➡Gradient of the graph is constant❌
➡gradient of the tangent of the graph represents acceleration❌
➡gradient of the tangent represents velocity✅
200
Unit of instantaneous velocity is;
m/s
201
If an object moves with constant speed then its acceleration always is;
Non-zero
202
The accelerating frame of reference which has constant acceleration is;
Freely falling body on earth
203
If a car moves from 15m/s to 5m/s in 10 sec, then the average acceleration is;
1 m/s2
204
The rate of change of displacement with respect to time is;
Velocity
205
When an object with a speed of 100ms-1 can just penetrate two planks of equal thickness. Then, the number of such planks penetrated by the same bullet when the speed is doubled will be:
8
206
A ball is just allowed to all from the window of a moving train, it will hit the ground following:
Parabolic Path
207
A particle moves along a straight line. The distance x describes time, t is given by the equation x = t^3 the acceleration at t=1
A =1
208
The vertical velocity of a ball thrown upward ___ with time.
Decreases literally
209
An ______ missile is called a ballistic missile.
➡Unpowered
➡Un-guided
210
A body is moving with an initial velocity of 2 kms-1. After a time of 50 sec, its velocity becomes 1.5 kms-1. Its acceleration will be;
10 ms-2
211
In an elastic collision, when a massive body collides with the light body at conditions m1 >>m2 and v2=0 ms-1, then the change in velocity will be written as;
➡v1' = v1
➡v2' = 0
212
If a force of 12N is applied to a body and its momentum its changed from 60kgms-1 to 36 kgms-1, then find the time during , which the force acts:
2 seconds
213
The time of projectile's flight is;
2vsinΘ/g
214
If the velocity of the body changes by an equal amount in equal amount in equal intervals of time, the body is said to have;
Uniform acceleration
215
For finding, the height of the projectile, the equation used is:
2aS = vf^2 - vi^2
216
One ball is thrown vertically upward with a velocity of 9.8 ms-2. If the takes 10 seconds to reach the highest point, then the acceleration of the ball is;
-9.8 ms-2
217
A ball is dropped from the roof of a very tall building. What is its velocity after falling for 5.0 sec?
49.0 ms-1
218
A projectile is launcehed at 45° to the horizontal with initial K, Energy E. Assuming air resistance to be negligible, what will be the kinetic energy of the projectile when it reaches its highest point?
0.50 E
(Initial Kinetic Energy = E)
➡1/2 mv^2 cos^2Θ = EcosΘ
219
Weight rather than mass be used in calculating:
The gravitational force between the two bodies
220
The ratio of displacement along the diameter and total distance along the circle:
1:π
221
Arshad is driving down 7th street. He drives 150 meters in 18 seconds. Assume he does not speed up or slow down. What is his speed?
8.33 m/s
222
The distance travelled by a moving car with a velocity of 15 m/s in 2 seconds, decelerates at 2m/s^2 is equal to:
26m
(S=vit +1/2 at^2)
223
The value of the ratio of displacement to distance is:
Equal or less than one
224
The numerical ratio of displacement to distance is;
Equal to or less than one
225
A bullet of mass m moving with velocity v is fired into a large wooden block of mass M of the bullet remains embedded in the wooden block, and the velocity of the system will be;
m/M+m x v
226
If the slope of the velocity-time graph is not constant at different points, then the body is moving with
Increasing acceleration
227
A cyclist is travelling at 15 ms-1 she applies brakes so that she doesn't collide with the wall in front of her distance of 18m. Calculate the magnitude of deaccleration;
6.3 ms-2
(2aS = vf^2 - vi^2)
228
Newton's first law of motion is also known as:
Law of inertia
229
If two objects of equal masses 'm' are moving towards each other with the same speed 'v' then what will be the total final momentum after elastic head-on collision?
0 kgms-2
230
For projectile motion in the absence of air resistance:
Horizontal acceleration is zero
231
The range of the projectile depends upon the velocity of the projection and the angle of projection is 45°. For a fixed velocity, when the angle of projection is larger than 45°. Which of the following is correct?
The height attained by the projectile will be more but the range is less
232
The slope of the distance-time graph will always be:
Positive
233
At what angle of projection of a projectile the range becomes half of its maximum value?
15°
(R= Rmax sin2Θ)
➡sin2(15) = 1/2
234
If we drop an object, its initial velocity is zero. How far will it fall in time 't'?
4.9t^2
(S=vit + 1/2 at^2)
235
The newton-second is a unit of;
Impulse
236
Which one of the following is the angle of projection of a projectile if its range is equal to its height:
76°
(4H = RtanΘ)
tanΘ=1/4
237
The product of force and time is equal to;
Change in momentum
238
At what angle of projection of a projectile the range becomes hal o its maximum value:
40°
239
Vertical velocity vs time graph for a projectile motion
Varies linearly
240
The magnitude of displacement is;
Straight line distance between the initial and final position
241
If the displacement is equal to 15 m and time is equal to 10 second average velocity is
1.5 m/s
242
Decrease in Velocity per unit time is called
Deacceleration
243
Slope of velocity time graph represents
Acceleration
244
An object is accelerating
A
When it speed the direction changes
245
What is the slope of a straight line graph of position vs time
Displacement
246
Coefficient the coefficient of restitution for a perfectly elastic collision is
Infinity
247
What is the accelerating force on the Diwali rocket if it's reject 0.05 kilogram of gases per second that have velocity of 400 m per second
20 N
(F = m(v/t)
248
If if mass is 2 kg and velocity is 35 m/s then momentum is
70 kgm/s
249
If velocity time graph shape is parallel to y axis then
Infinity
250
A person moves along a circular track and covers half of the path as shown in figure. What will be the ratio of its distance to displacement covered?
π/2
251
An athlete completes one round of a circular track of radius R in 40 sec. What will be his displacement at the end of 3 min. 20 sec?
Zero
252
A man leaves his house for a cycle ride. He comes back to his house after half-an-hour after covering a distance of one km. What is his average velocity for the ride?
Zero
253
Stopping distance of a moving vehicle is directly proportional to
Square of initial velocity
254
The ratio of displacement along diameter and total distance along circle:
1:π
255
In 1.0 second a particle goes from point A to point B moving in a semi-circle a radius 1.0 m (figure). The magnitude of the average velocity is
2.0 m/s
256
A helicopter is flying at 3564 m above ground. If an angle of 30° is subtended at a ground point by the helicopter position 100s apart, what is the speed of the helicopter
20 m/s
(tan 30°=x/3564)
257
A car travels equal distance in the same direction with velocities 60 km h–1, 20 km h–1 and 10 km h–1 respectively. The average velocity of the car over the whole journey of motion is
5 m/s
258
A train takes 1 hour to go from one station to the other. It travels at a speed of 30 kmh–1 for first half hour and at a speed of 50 kmh–1 for the next half hour. The average speed of the train is:
4p km/h
259
A moves with 65 km/h while B is coming back of A with 80 km/h. The relative velocity of B with respect to A is
15 km/h
260
A constant force F changes the velocity of a 80kg sprinter from 3ms-1 to 4ms-1 in 0.5 sec. The acceleration of sprinter will be
2.0 m/s
261
A ball is projected upwards with an initial velocity as shown in the figure. It comes back after sometime and strikes ground with the same velocity but pointing downward. What is the angle between acceleration when moving upward to acceleration coming down?
0°
(Direction of acceleration due to gravity toward earth center.)
262
A baseball is thrown vertically into the air. The acceleration of the ball at its highest point is:
g , down
263
A passenger in a moving train tosses a coin. If the coin falls behind him, the train must be moving with
An acceleration
264
The displacement-time graphs of two particles A and B are straight lines making angles of 30∘and 60∘respectively with the time axis. If the velocity of A is vA
and that of B is vB , the value of vA/vB is
A
1/3
265
The slope of the tangent of a point on d-t graph gives the magnitude of
Instantaneous Velocity
266
If d-t curve is a straight line, it shows that body is
Uniform Velocity
267
The engine of a car produces an acceleration of 6 ms–2 in the car. If this car pulls another car of the same mass, then the acceleration would be
3 m/sec
268
A cricket player catches a ball of mass 100 g and moving with a velocity of 25ms-1. If the ball is caught 0.1s, the force of the ball exerted on the hand of the player is:
25N
269
A cricket ball of mass 0.5 kg strikes a bat normally with a velocity of 30 ms-1 and rebounds with a velocity of 20 ms-1 in the opposite direction. The impulse of the force exerted by the ball on the bat is
25 N.s
270
When the velocity is doubled
Momentum is doubled
271
The momentum is most closely related to
Impulse
272
The motion of a rocket is based on the principle of conservation of:
Linear Momentum
273
A billiard ball moving with a speed of 5 m/s collide with an identical ball, originally at rest. If first ball stops dead after the collision, then second ball will move forward with speed of
5 m/s
(When two identical balls collide elastically their velocities are interchange.)
274
When a very heavy ball ‘B1’ collide with a stationary target ‘B2’ of negligible mass, after collision the final velocity of ball ‘B2’ will
Become doubled as compared to B1
275
A 10 kg object collides with stationary 5 kg object and after collision they stick together and move forward with velocity 4ms−1. What is the velocity with which the 10 kg object hit the second one
6 m/s
276
When a ball bounces back from floot such that sound and heat is produced then collision
➡️ Must be inelastic
➡️ Momentum is conserved but K.E is not conserved
277
A ball of mass 2 kg travelling at 8 ms-1 strikes a ball of mass 4 kg travelling at 2 ms-1. Both balls are moving along the same straight line as shown
After collision, both balls move at the same velocity v. What is the magnitude of the velocity v?
4 m/s
278
Two similar spheres, each of mass m and travelling with speed v, are moving towards each other.
The spheres have a head on elastic collision. Which statement is correct?
The total kinetic energy after impact is mv2
279
Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together.
What is the speed of the trucks after the collision?
V/4
280
A ball is dropped from a height of 10 m. It is embedded 1 m in sand and stops. In this process
Only momentum is conserved
281
When two bodies collide elastically then the quantity conserved is
➡️Kinetic Energy
➡️Momentum
282
A cricket ball is hit at 45° to the horizontal with a kinetic energy K. The kinetic energy at the highest point is
K/2
283
A projectile is projected upwards with an angle of with x-axis at shown in the figure such that its K.E at projection is. What will be its K.E at the top?
50J
284
At which point for a projectile its kinetic energy is completely converted into potential energy
Not possible
285
A 1000-kg airplane moves in straight flight at constant speed. The force of air friction is 1800 N. The net force on the plane is:
Zero
286
A body is thrown horizontally from the top of a tower of height 5 m. It touches the ground at a distance of 10 m from the foot of the tower. The initial velocity of the body is (g = 10 ms-2)
10 m/s
287
A projectile of mass m is the thrown with a velocity v making an angle of 45° with the horizontal. The change in momentum from departure to arrival along vertical direction, is
√2 mv
288
At maximum height in projectile motion the horizontal component of velocity will :
Constant
289
An aero plane is flying horizontally with a velocity of 10 m/s and at a height of 1960 m. When it is vertically above a point A on the ground, a bomb is released from it. The bomb strikes the ground at point B. The distance AB is (ignoring air resistance)
200 m
290
A projectile is fired horizontally from a 490m high cliff with a velocity of 80ms‑1. The time taken by the projectile to reach the ground is
10 sec
291
A projectile is fired horizontally from a 490m high cliff with a velocity of 80ms‑1. The time taken by the projectile to reach the ground is
10 sec
292
For projectile motion in the absence of air resistance:
Horizontal acceleration is zero
293
The angle of projection for which the maximum height and the horizontal range of a projectile are equal to
tan ^-1 (4)
294
Two balls projected at 30o and 60o with same initial velocities. The ratio of their maximum heights is:
1:3
295
A projectile is projected with kinetic energy (K.E). If it has the maximum possible horizontal range, then its kinetic energy at the highest point will be:
0.5 K.E
296
A body is thrown with a velocity of 9.8 m/s making an angle of 30o with the horizontal. It will hit the ground after a time
1 sec
297
If a projectile is thrown with 19.6m/s velocity at 30° with x-axis, time taken to reach highest point?
1 sec
298
Time of flight of projectile is
2vinsinθ/g
299
A missile is fired for maximum range with a initial velocity of 20 m/s. If g=10m/s2, the range of the missile is
40m
300
A missile is fired for maximum range with a initial velocity of 20 m/s. If g=10m/s2, the range of the missile is
40m
301
A body is projected from a point with different angles of projections 20°, 35°, 45°, and 60° with horizontal but with the same initial speed. Their respective horizontal ranges are R1, R2, R3 and R4. Identify the correct order in which the horizontal ranges are arranged in increasing order:
R1, R4, R2, R3
302
A body is projected from a point with different angles of projections 20°, 35°, 45°, and 60° with horizontal but with the same initial speed. Their respective horizontal ranges are R1, R2, R3 and R4. Identify the correct order in which the horizontal ranges are arranged in increasing order:
R1, R4, R2, R3
303
For a long range and greater precision:
Powered and Guided Missiles are used
304
Accurate value of instantaneous velocity can be obtained if:
Δt ➡0
305
At the highest point , the velocity of projectile is:
Minimum
306
The distance travelled by a moving car with velocity 15 m/s in 2 seconds, deaccelerated at 2 m/s2 is equal to:
26 m
307
How far does a car travel in 3s if its initial velocity is 2 m/s and its acceleration is 2m/s2 in forward direction?
15 m
308
A ball is in free fall. Upward motion is taken to be the positive direction. The displacement of the ball during a short time interval is:
➡Positive during ascent
➡Negative during descent
309
The ratio of impulse to time is:
FOrce
310
A force of 5N acts on a body of 5kg for 5ec. The rate of change of momentum is;
5N
311
If the water falls from a dam into a turbine where 1.6m below, then velocity of water at the turbine is:
19.6 m/s
312
For range to have maximum value, the function sin2Θ should have value:
1
313
Which of given is correct equation or instantaneous velocity of projectile:
v = √vi^2 + g^2t^2 - 2vgtsinΘ
314
Gravels are dropped on a conveyor belt at the rate of 0.5 kg/sec. The extra force required in Newton's to keep the belt moving at 2m/s is:
1
315
Q
The rate of chagne o angualr momentum is equal to:
Torque
316
Velocity and acceleration are in the same direction when:
Velocity of a car is increasing on a straight road
317
A racing car traveling with constant acceleration increases its speed from 10 m/s to 50 m/s over a distance of 60m. How long does it take?
2.0 sec
318
Q
The "reaction" force does not cancel the "action" force because:
They act on different bodies
319
The slope of v-t graph of uniform velocity is:
0
320
No body begin to move or comes to rest itself is statement of:
Abu Ali Sena
321
Uniform constant retarding force is applied in order to stop a truck if its speed is doubled then the distance traveled by it will be:
Four times
322
I water strikes normally to a wall, then force exerted by wall on water is given by:
-m/t v
323
A ball is thrown horizontally from the top of a tower. What happens to the horizontal componenet of its acceleration?
Zero
324
Escape velocity of a body is independent of:
Mass of body
325
A heavy and lighter body are dropped from the top a tower. Which will reach the ground first.
Reach simultaneously
326
When the velocity is doubled:
Momentum is doubled
327
A balloonist is ascending at a velocity of 12m/s and acceleration 2 m/s2. A packet is dropped from it when it is at a height of 65m from the ground, it drops a packed. Time taken by the packed to reach the ground is:
5 sec
328
When a bomb explodes which law of conservation will hold:
➡Momentum
➡Energy
329
Measurement of inertial is associated with:
Mass of body
330
Height of projectile is calculated by:
H = v^2sin^2Θ/2g
331
If momentum of a body is doubled then its K.E become:
4 times
332
A body is rotating with a constatn angular velocity of 20 rad/s in time 20 sec. What is the rate of change of angular momentum?
20Nm
333
3rd law o motion expalins:
Existence of pair of forces in nature
334
The direction of linear velocity of a body moving in a circle is;
Along the tangent
335
A shell of mass "m" moving with velocity "v" suddenly explodes into two pieces. One part of mass m/4 remains stationary. The veloicty of the other part will be:
4v/3
336
Two masses m1 and m2 are initially at rest with a spring compressed between them. What is the ratio of the magnitude of their velocities after the spring has been released?
m2/,m1
337
When a force of 100N acts on a body of mass 50 kg then accleration produced is:
2 m/s
338
A body is dropped from a tower reaches ground in 4sec, height of tower is:
80m
339
A truck takes 20sec to travel the first 80m, and another 10sec to travel a further 70m. What is the average speed
5.0 m/s
340
When a force of 100N acts on a body of mass 50kg then acceleration produced is:
2 m/s2
341
Time taken by an engine of 10kW to lift a mass of 2kg to a height of 5m is:
10^-2 sec
342
Range of projectile is same as that for Θ and 2Θ. The value of Θ is:
30°
343
The displacement of a freely falling body is proportional to the:
Square of time of fall
344
In the case of a projectile fired at an angle equally inclined to the horizontal and vertical with velocity v, the horizontal range is:
v^2 / g
345
Fuel mas is how much percentage of the launch-mass of arocket?
80%
346
If the slope of a velocity time graph gradually decreases then the body is said to be moving with:
Negative acceleration
347
A ball i projected at 45°. If horizontal range is 10m, velocity of projection is:
10 m/s
348
If the displacement of a particle is zero then the distance covered:
May or may not be zero
349
A body is thrown upwards and reaches its maximum height. At that position:
➡Its velocity is zero
➡Its acceleration is accelerations due to gravity
