forces

Question 1

what is a scalar quantity

Answer 1

. A quantity that only has a magnitude
.doesent have an direction

Question 2

what is a vector quantity

Answer 2

.a quantity that has both magnitution , but also associated direction

Question 3

how can a vector quantity be drawn and what does is show

Answer 3

. as an arrow
.the length of the arrow represents the magnitude ]
.the arrow points in the associated direction

Question 4

what is a force

Answer 4

a push of pull acting on an object due to an interaction with another object

Question 5

give 3 examples of contact forces

Answer 5

.friction
.air resistance ]
.tension

Question 6

give 3 examples of non-contact forces

Answer 6

.gravitational forces
.electrostatic forces
.magnetic forces

Question 7

is force a vector or scalar quantity

Answer 7

.vector it has magnitude and asscociated direction

Question 8

give 3 examples of vector quantities

Answer 8

. velocity
.displacement
.force

Question 9

give 3 examples of scalar quantities

Answer 9

. temperature
.time
.mass
.speed
.distance
.energy

Question 10

what is weight

Answer 10

the force that acts on an object due to gravity and objects mass

Question 11

what quantities does weight depend on

Answer 11

.the objects mass
.the gravitational field strength at the given position in the field

Question 12

what peace of equiptment can be used to measure an objects weight

Answer 12

spring balance
newton meter

Question 13

what is the name given to the single force that is equivalent to all the other forces acting on a given object

Answer 13

the resultant force

Question 14

what does it mesn if a force is said to do work

Answer 14

the force cuauses an object to be displaced through a distance

Question 15

what occurs when work is done against frictional forces

Answer 15

. a rise in temp of the object
.kinetic energy is converted to heat

Question 16

work done equation

Answer 16

work done = force times distance

Question 17

why does air resistance slow down a projectile

Answer 17

. the object does work against the air resistance
.kinetic energy is converted into heat , slowing down the object

Question 18

explain the relationship between the force applied and the extension of an elastic object

Answer 18

the extension is directly proportional to the force applied , provided that the limit of proportionality is not exceeded

Question 19

what is meant by a inelastic deformation

Answer 19

. the object doesent turn to its orignal shape when the force is removed

Question 20

equations resulting force , spring constant , and extension

Answer 20

force= spring constant times exstension

Question 21

what type of energy is stored in a spring when it is stretched

Answer 21

elastic potential energy

Question 22

what can extension be replaced with in the equation for spring force

Answer 22

compression

Question 23

does a distance quantity require a specific direction

Answer 23

no specific direction is required so it is an scalar quantity

Question 24

if an object moves 3 meters to the left and then 3 meters back to its initial position. what is the objectc total displacement

Answer 24

. the object has zero displacement
.displacement is a vector quanitity so it also involves direction
.the object starts and ends at the same point

Question 25

state a typical value for the speed of sound

Answer 25

330ms

Question 26

what is the typical value for human walking speed

Answer 26

1.5ms

Question 27

what is the typical value for human running speed

Answer 27

3ms

Question 28

state the equation linking distance speed and time

Answer 28

distance= speed times time

Question 29

how can a speed be calculated from a distance time graph

Answer 29

the speed is equal to the gradient of the graph

Question 30

state the equation for the average accleration of an object

Answer 30

accelaration= change in velocity / time taken

Question 31

what can be said about an resultant force acting on an object , when it is falling at terminal velocity

Answer 31

. the resultant force is zero .when at a terminal velocity , the object is moving at a constant speed and so isnt accelarating

Question 32

state newtons first law for a stationary object

Answer 32

if the resultant force on a stationary object is zero, the object will remain at rest

Question 33

state newtons first law for a moving object

Answer 33

. if a resultant force on a moving object is 0 , the object will remain at constant velocity , same speed at same direction

Question 34

what can be said about the braking forces and driving forces , when a car is travelling at constant velocity

Answer 34

. the braking forces are equal to the driving forces

Question 35

if an object changes direction but remains at a constant speed , is there a resultant force

Answer 35

since there is a change in direction , there is a change in velocity and so there must be a resultant force

Question 36

state the defining equation for newtons second law

Answer 36

resultant force= mass times accelaration

Question 37

state newtons second law in words

Answer 37

. an objects acceleration, is directlly proportional to the resultant force acting on it and inversely proportional to its mass.

Question 38

what is the symbol used to represent an approximate value

Answer 38

a squiqly line

Question 39

state newtons third law

Answer 39

whenever two objects interact , the forces that they exert on eachother are always equal and opposite.

Question 40

what is the stopping distance of a vehicle equal to

Answer 40

the sum of braking and thinking distance

Question 41

for a given braking distance , if the vehicles speed is increased . what can be said about its stopping distance

Answer 41

the stopping distance is increased with an increase in speed.

Question 42

give a typical range of value for human reaction times

Answer 42

0.2-0.9 seconds

Question 43

give 3 factors which can affect a drivers reaction time

Answer 43

.tiredness .drug .alchahol

Question 44

give 2 factors which may affect braking distance

Answer 44

. adverse road conditions .poor tyre,brake conditions

Question 45

desribe the energy transfers that take place when a car applies its breaks

Answer 45

. work is done by the friction force between the brakes and wheel .kinetic energy of the wheel is converted to heat and is disspated to the surroundings through the brake discs

Question 46

to stop a car in a given distance , if its velocity increased , what must happen to the braking force applied

Answer 46

the braking force must also be increased

Question 47

state two consequences of a vehicle undergoing very large decelerations

Answer 47

. kinetic energy converted to heat is very high , causing breakes to overheat .loss of control of the vehicle