Forces

Question 1

vector

Answer 1

size and direction

Question 2

scalar

Answer 2

size only

Question 3

examples of vector

Answer 3

weight
displacement
force
acceleration
velocity

Question 4

examples of scalars

Answer 4

speed
distance
energy
time
temperature

Question 5

unit of force

Answer 5

newtons-N

Question 6

unit for mass

Answer 6

kilograms - KG

Question 7

unit for weight

Answer 7

newtons - N
or
newtons per kilogram - N/Kg

Question 8

unit for energy

Answer 8

joules - J

Question 9

speed =..

Answer 9

distance/time

Question 10

what does a diagonal ( / ) line mean in a distance time graph

Answer 10

the speed is constant

Question 11

what does a horizontal ( — ) line mean on a distance time graph

Answer 11

stationary

Question 12

acceleration =…

Answer 12

(v - u) / t

Question 13

what does a diagonal ( / ) line mean on a velocity time graph

Answer 13

constant acceleration

Question 14

what does a straight ( — ) line mean on a velocity time graph

Answer 14

constant speed

Question 15

how to find distance using a speed time graph

Answer 15

area under the graph
try to split it into triangles and rectangles

Question 16

area of triangle

Answer 16

(bxh)/2

Question 17

resultant force

Answer 17

the force leftover from adding two forces

Question 18

newtons first law

Answer 18

a moving object will continue to move at the same speed and direction unless an external force acts on it

a stationary object will remain stationary unless an external force acts on it

Question 19

how can an object moving in a circle be accelerating?

Answer 19

the direction is changing, meaning the velocity is changing, so there is a constant acceleration as acceleration is the change in velocity

Question 20

centripetal force

Answer 20

the resultant force towards the centre of the cirlcle
acceleration is always in the direction of the resultant force

Question 21

newtons second law

Answer 21

size of acceleration means the size of the force
direction of the acceleration must be the direction of the force

Question 22

force = ….

Answer 22

mass x acceleration

Question 23

equation for force using momentum

Answer 23

f=mv-mu/t

Question 24

how does an airbag save you from large injuries?

Answer 24

increases the time for the human to stop
so there is a longer change of momentum overtime
which reduces the force

Question 25

equation for impulse

Answer 25

force x time

Question 26

impulse definition

Answer 26

average force and time of contact for a collision

Question 27

if force is applied for longer then momentum is.....

Answer 27

greater

Question 28

newtons third law

Answer 28

If A exerts a force on B, then B exerts an equal but opposite force on A e.g, I push on a wall, the wall pushes back at me

Question 29

momentum = ...

Answer 29

mass x velocity

Question 30

efficiency = ...

Answer 30

useful energy/total energy

Question 31

what is meant by closed system?

Answer 31

no outside forces acting on an objetc

Question 32

thinking distance = ...

Answer 32

speed x reaction time

Question 33

stopping distance = ...

Answer 33

thinking distance + breaking distance

Question 34

when you double the speed, the thinking distance...

Answer 34

doubles

Question 35

if you double the speed, you quadruple the...

Answer 35

breaking distance and kinetic energy this is because breaking distance is linked to kinetic energy and it takes 4 x the distance to remove 4 x the energy

Question 36

breaking distance

Answer 36

the distance covered to transfer all the kinetic energy of the car to heat energy in the breaks

Question 37

kinetic energy = ...

Answer 37

0.5 x m x v^2

Question 38

exam style question: a man falls at a constant speed, as he falls he is losing GPE. Where does that energy go?

Answer 38

since the man is falling at a constant velocity, the energy is most likely transferred into heat energy from friction with air resistance, which dissipates into its surroundings

Question 39

weight = ...

Answer 39

mass x gravity, (10)

Question 40

what happens to wasted energy

Answer 40

dissipates into its surroundings

Question 41

what happens to the GPE when an object accelerates downwards

Answer 41

GPE is being transferred to kinetic energy

Question 42

V^2 - U^2 = ...

Answer 42

2 x a x d

Question 43

GPE = ...

Answer 43

mass x gravitational field strength x height

Question 44

practical question: why is the ramp slanted during a trolley cart experiment?

Answer 44

this reduces the external forces, friction, from ruining the experiement

Question 45

practical question: why can weights only be transferred from the cart to the hanger during the trolley experiment?

Answer 45

the mass cannot change otherwise it would ruin the experiment

Question 46

explain why the actual speed of an object just before it hits the floor would be different from traditional calculations? (2 marks)

Answer 46

- some of the energy would be transferred to heat into the surroundings - so the speed would be less than calculated

Question 47

Describe one way in which energy is transferred inefficiently when you ride a bicycle (2 marks)

Answer 47

- friction in the chains will transfer energy into heat