Motion and Force Flashcards Preview

RGS 3rd Form Physics MAC > Motion and Force > Flashcards

Flashcards in Motion and Force Deck (78)
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1
Q

In which part of the graph (A, B or C) is the object moving the fastest?

A

A

  • gradient of the line is the steepest
  • more distance covered per time
  • faster speed
2
Q

What is the difference between the force upthrust and reaction force?

A

Up thrust is created when an object displaces a fluid, such as a boat displacing water.

Reaction force is the upward force on a block which is resting on a solid surface.

3
Q

What is the SI unit for force?

A

newton or N

4
Q

What type of force is created between two magnets?

A

magnetic force

This force can be attractive or repulsive

5
Q

In which graph/s is the object travelling at a constant speed?

A

a) and e)

gradient is constant throughout

6
Q

If a person has a mass of 100 kg on Earth. What will their weight be?

The gravitational field strength of the Earth is 10 N/kg

A

W=mg

W = 100 kg x 10 N/kg

W = 1000 N

7
Q

What feature of a velocity-time graph gives the acceleration?

A

gradient of velocity-time graph

8
Q

Masses are attracted to each other. Planets are attracted to each other. Name the force acting between them.

A

Gravitational force

9
Q

Describe what is happening in the graph and explain how you know.

A

The object is accelerating or speeding up from the starting position

The gradient of the line is increasing, therefore velocity is increasing.

10
Q

Which sketch (red or green) represents a faster velocity?

A

Green- more steep line

Object is covering more distance per time

11
Q

If an object has a 50 N force acting North and a 50N force acting south, what is the resultant force?

A

50 N - 50 N = 0 N

12
Q

What is the SI unit for displacement or distance travelled?

A

metre or m

13
Q

F= ma

Make acceleration the subject of the equation

A

a = F/m

14
Q

Which of the following quantities are vectors?

mass

acceleration

force

speed

velocity

time

A

acceleration

force

velocity

15
Q

In which part of the graph (A, B or C) is the object travelling back to the start.

A

C

-gradient of the line is negative

velocity is negative

-travelling in opposite direction to part A

16
Q

What is the equation for average speed?

A

average speed = total distance travelled/ time taken

17
Q

What type of force acts forward on a rocket?

A

Thrust

Thrust is created when an object throws something out in one direction- such as gases.

18
Q

What type of force is reduced if an object is streamlined?

A

air resistance

19
Q

Rockets can push gas out and downward and the rocket moves upward. What is the name of this upward force on the rocket?

A

Thrust

20
Q

What feature of a velocity-time graph gives the acceleration?

A

gradient of velocity-time graph

21
Q

What feature of a velocity-time graph gives the distance travelled?

A

area under a velocity-time graph

22
Q

In which graph/s is the object decelerating?

A

d)

gradient is getting less steep

23
Q

What can forces do to an object?

A
  • change the speed of the object (accelerate or decelerate)
  • change the direction of the object
  • change the shape of the object
24
Q

A horizontal line on a velocity-time graph shows?

A

constant velocity, no acceleration

25
Q

A horizontal line on a distance-time graph shows what?

A

That the object is not moving, has zero speed

26
Q

If a book is a rest on a table, what two forces are acting on it.

A

downward gravitational pull (or weight)

upward reaction force from table

27
Q

If an object accelerates at 10 m/s2. How fast would it be travelling after 10 s if it started at rest?

A

It will gain 10 metres per second every second.

After 10 s if should be travelling at 100 m/s!

28
Q

What feature of a distance-time graph gives the velocity?

A

gradient of distance-time graph

29
Q

Which ticker tape shows an object which is decelerating?

A

ticker tape Z

  • dots get closer together
  • object is covering less distance per unit time
  • object is slowing down
30
Q

What can be done to reduce friction when an object is sliding on a surface?

A
  • use oil or grease on the surfaces
  • make the surfaces smoother
  • blow air between the surfaces
31
Q

In which part of the graph (A, B or C) is the object stopped?

A

B

Gradient is zero therfore speed is zero- obejct is not moving

32
Q

What type of force acts upward on the wing of an aeroplane?

A

Lift

33
Q

What is the SI unit for acceleration?

A

metre per second squared or m/s2

34
Q

In the equation W=mg, what is g (gravitatinal field strength or gravity) measure in?

A

gravity g is measure in N/kg

It is the force which acts on every kg of mass

35
Q

Describe what is happening to the velocity in this distance time graph.

A

A –> B velocity is constant

B –> C velocity is zero

C –> D velocity is increasing

D –> E velocity is zero

E–> F velocity is constant but opposite direction

36
Q

F= ma

Make mass the subject of the equation

A

m = F/a

37
Q

What is used to measure force?

A

A force meter

38
Q

define acceleration

A

Acceleration is the rate of change of speed

OR

The change in speed per unit time

39
Q

In which graph/s is the object travelling at a constant speed?

A

a) and e)

gradient is constant throughout

40
Q

Name three scalar quantites

A

time

mass

speed

distance

energy

41
Q

What is the equation which links weight, mass and gravitational field strength?

A

Weight = mass x gravitational field strenght

W = mg

42
Q

How would you sketch a d-t graph of an object accelerating away from a point

A

The gradient of the line is increasing

speed is increasing

object is accelerating

43
Q

What is the SI unit for time?

A

seconds or s

44
Q

What is Newton’s second law?

A

F = ma

An object will accelerate or decelerate if an unbalanced force is acting on it.

F is the resultant force

45
Q

What force is created in the rope of a swing?

A

tension

46
Q

This upward force on an object is equal the weight of the fluid (water) the object displaces. Name the force.

A

Up thrust

47
Q

What does this ticker tape show about the movement of the object?

A
  • dots are evenly spaced
  • object is covering the same distance per unit time
  • object is travelling at a constant speed, it is not accelerating
48
Q

What is the SI unit for velocity or speed?

A

metre per second or m/s

49
Q

In which graph/s is the object decelerating?

A

d)

gradient is getting less steep

50
Q

What type of force is created between two charged particles?

A

electrostatic force

This can be attractive or repulsive

51
Q

What is the difference between a vector and scalar quantity?

A

scalar quantities have magnitude only

vector quantites have both magnitude and direction

52
Q

How do you find the instantaneous speed from a distance time graph?

A

Calculate the gradient of the line at that instant.

Draw a triangle and calculate

speed = rise/ run - distance travelled/ time

53
Q

What feature of a distance-time graph gives the velocity?

A

gradient of distance-time graph

54
Q

If a person has a mass of 100 kg on Earth. What will their weight be?

The gravitational field strength of the Earth is 10 N/kg

A

W=mg

W = 100 kg x 10 N/kg

W = 1000 N

55
Q

speed =distance / time

rearrange for distance or d

A

distance = speed x time

56
Q

What does this ticker tape show about the movement of the object?

A
  • dots are moving further apart
  • object is cover more distance per unit time
  • object is speeding up, accelerating
57
Q

How is mass different from weight?

A

Mass is the amount of matter an object is made of

(measured in kg or g)

Weight is the gravitational pull on the object which depend on the gravitational field strength of the planet

(measured in Newtons or N)

58
Q

Why does the moon have less gravity (or gravitational field strength) than the Earth?

A

The moon has less mass than the Earth

59
Q

Sketch a d-t graph of an object stationary at 3 metres.

A
60
Q

If a person has a mass of 100 kg on Earth. What will their mass be on the moon?

The gravitational field strength of the moon is 1/6th that of the Earth

A

100 kg

Mass the amount of matter an object is made of. It does not change when on another planet

61
Q

What does this ticker tape show about the movement of the object?

A
  • dots are evenly spaced
  • object is covering the same distance per unit time
  • object is travelling at a constant speed, it is not accelerating
62
Q

Which ticker tape shows an object which is decelerating then accelerating?

A

ticker tape E

  • dots get closer together, then further apart
  • object is covering less distance per unit time, then more distance per unit time.
  • object is slowing down then speeding up, decelerating, then accelerating
63
Q

If a person has a weight of 600N on Earth. What will their mass and weight be on the moon?

  • The gravitational field strength of the Earth is 10 N/kg*
  • Gravity on the moon is 1/6 th the gravtity on Earth*
A

Weight will be 1/6th that on the Earth which is 100N

To calculate mass on Earth

W= mg

m = W/g

mass = 600 / 10 = 60 kg

Mass on the moon is the same- 60kg

64
Q

In which graph/s is the object at rest?

A

b)

gradient is zero

65
Q

What is the relationship between force, mass and acceleration?

A

Force = mass x acceleration

F = ma

This is called Newton’s second law

66
Q

F= ma

Make mass the subject of the equation

A

m = F/a

67
Q

What does this ticker tape show about the movement of the object?

A
  • dots are moving further apart
  • object is cover more distance per unit time
  • object is speeding up, accelerating
68
Q

In which part of the graph (A, B or C) is the object stopped?

A

B

Gradient is zero therfore speed is zero- obejct is not moving

69
Q

What is the unit for acceleration?

A

m/s2

70
Q

What type of force is created between two magnets?

A

magnetic force

71
Q

Which ticker tape shows an object which is decelerating then accelerating?

A

ticker tape E

  • dots get closer together, then further apart
  • object is covering less distance per unit time, then more distance per unit time.
  • object is slowing down then speeding up, decelerating, then accelerating
72
Q

I am a type of force that is created from a fluid being displaced.

What force am I?

A

Up thrust

73
Q

speed = distance /time

rearrange for time or t

A

time = distance / speed

74
Q

What is the equation for acceleration?

A

a = (v-u)/t

OR

a = change in velocity / time

75
Q

Why are arrows perfect for drawing forces (a vector) quantities?

A

The arrow size can represent the magnitude of the force. The arrow direction can represent the direction the force is acting in.

76
Q

If a person has a mass of 100 kg on Earth. What will their mass be on the moon?

The gravitational field strength of the moon is 1/6th that of the Earth

A

100 kg

Mass the amount of matter an object is made of. It does not change when on another planet

77
Q

In which part of the graph (A, B or C) is the object moving the slowest?

A

C

  • gradient of the line is the shallowest
  • less distance covered per time
  • slower speed
78
Q

If an object is decelerating at 2 m/s2, how fast is it going after 4 seconds if it was travelling at 14 m/s?

A

It will lose 2 metres per second every second.

after 4 seconds it will decrease its velocity by 8 m/s

14 - 8 = 6 m/s