Flashcards in P3 Deck (41):

0

## How can you calculate speed?

###
Speed=

Distance traveled ➗ time taken

1

## What is the triangle for distance, speed and time?

###
D

➖➖➖➖➖➖➖

S ✖️ T

2

## How can you calculate the speed of a car from pictures taken by a speed camera?

###
Speed of car=

Distance travelled between pictures

➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖

Time taken between pictures

3

## What is acceleration measured in?

### - metres per second squared

4

## How can you calculate the acceleration of an object?

###
Acceleration=

Change in speed ➗ time taken for change

5

## What is Relative speed?

### - the speed of an object, relative to another object that is being treated to be at rest

6

## Give an example of something weight causes?

### - weight causes an apple falling from a tree to speed up as it falls

7

## Give an example of something Friction causes?

### - friction causes a car to slow down

8

## How do you work out Resultant force?

### Resultant force= mass(kg) ✖️ acceleration

9

## How can you work out stopping distance?

###
Stopping distance=

Thinking distance ➕ braking distance

10

## What is thinking distance?

###
- the distance travelled by the vehicle from the point the driver realises he needs to brakes to when he applies the brakes

11

## What is Braking distance?

### - the distance it takes the vehicle to stop once the driver applies the brakes

12

## What can increase a vehicles braking distance?

###
- If the mass of the vehicle is increases, a loaded vehicle has a greater kinetic energy

- if the friction between the tyres and the road is decreased, a wet or greasy road surface reduces the amount of friction.

- if the braking forces applied is decreased, a smaller force is exerted by the brake pads on the wheel if the wheel discs if the pads are worn

- if the vehicle is travelling faster

13

## How can the thinking distance of a car stopping be increased?

###
- if the vehicle is travelling faster

- if the driver is ill, tired, or under the influence of alcohol or drugs

- if the driver is distracted or isn't concentrating

14

## How do you calculate the weight of an object?

### Weight = mass ✖️ gravitational field

15

## What is work done equal to?

### - the energy transferred

16

## What does the amount of work done depend on?

###
- the size of the force

- the distance the object has moved

17

## How can you calculate the work done?

###
Work done =

Force applied ✖️ distance moved in direction of force

18

## What is power a measurement of?

### - how quickly work is done

19

## How can you work out power using work done and time?

### Power = work done ➗ time

20

## How can power be calculated using force and velocity?

### Power = force ✖️ velocity

21

## What is kinetic energy?

### - the energy an object has because of its movement

22

## What does kinetic energy depend on?

###
- mass

- speed

23

## If a car moves at a greater speed, or has a greater mass, how is the kinetic energy affected?

### - the kinetic energy is greater

24

## How can you calculate kinetic energy?

###
Kinetic energy =

1/2 ✖️ mass ✖️ speed squared

25

## What does fuel consumption depend on?

###
- the energy required to increase the kinetic energy

- the energy required to work against friction

- driving style, speed and road conditions

26

## How can frictional forces be reduced?

###
- changing the shape of the object

- using a lubricant

27

## Name the 4 safety features cars have?

###
- seat belts

- airbags

- crumple zone

- collapsible steering column

28

## What is a cars safety cage?

###
- a metal cage which strengthens the cabin section of the car.

- prevents the vehicle from collapsing when upside down or rolling

29

## Name the two safety features on a car which prevent accidents?

###
- anti lock braking system, prevent tyres from skidding

- traction control, prevents car from skidding when accelerating

30

## What is momentum?

### - a measurement of the state of motion of an object as a product of its mass and velocity

31

## What happens to a cars momentum when the car slows down?

### It decreases

32

## How can you work out momentum?

### Momentum= mass✖️ verlocity

33

## How can you calculate the force of momentum?

###
Force=

Change in momentum ✖️ time taken

34

## How can the stopping forces experienced in a collision be reduced?

###
- increasing the stopping collision time

- increasing the stopping or collision distance

35

## What happens when a skydiver jumps, before the parachute opens?

###
1- when the skydiver jumps, he is initially accelerates due to the force of gravity.

2- as he falls, he experiences the frictional force of air resistance in the opposite direction, at this point, weight is greater than resistance, so, he continues to accelerate.

3- as his speed increases so does the air resistance working against him.

4- air resistance increases until it is equal to weight, the resulting force now acting on him is zero and his falling speed becomes constant, this is TERMINAL SPEED

36

## What happens when a skydiver jumps, after the parachute opens?

###
1- when the parachute is opened, unbalanced forces act again because the upwards force of resistance is greatly increased and bigger that weight

2- the increase in resistance decreases his speed

3- resistance decreases until it is equal to weight, a new TERMINAL SPEED is created

37

## What is the gravitational potential energy of an object?

###
- the energy stored due to:

> it's mass

> it's position in the Earths gravitational field

38

## How can you calculate Gravitational potential energy?

###
GPE=

Mass ✖️ gravitational field strength ✖️ vertical height

39

## What isEarth's Gravitational field strength?

###
- 10N/kg,

> every 1kg of matter near the Earths surface expire cars a downward force of 10N

40