P2

Question 1

What is speed measured in?

Answer 1

metres per second m/s

Question 2

What is distance measured in?

Answer 2

Metres

Question 3

What is time measured in?

Answer 3

Seconds

Question 4

What is velocity?

Answer 4

A vector quantity
Has size - speed
Has a direction
Measured in metres per second

Question 5

What is acceleration?

Answer 5

The rate of change of velocity

Question 6

What is acceleration measured in?

Answer 6

Metres per second per second

Question 7

How do you calculate acceleration?

Answer 7

The gradient on a velocity time graph

Question 8

How to you find the distance on a velocity time graph?

Answer 8

Calculate the area underneath

Question 9

What does a resultant force indicate?

Answer 9

Change in velocity (acceleration or deceleration)

Question 10

What was Newton’s first law?

Answer 10

If the resultant force on an object is zero it will either-
Remain at rest or
continue moving at constant velocity

Question 11

What effects thinking distance?

Answer 11

• How fast you’re going (the faster you’re going, the further you’ll go)
• Capability e.g. tiredness, drugs, alcohol

Question 12

What effects braking distance?

Answer 12

• How fast you’re going ( the faster you’re going, the further go)
• How good your brakes are (worn or faulty brakes will increase the braking time)
• How good the tires are ( Minimum tread depth of 1.6mm to get rid of water in wet conditions)
• How good the grip is (dependant on road surface, weather conditions and tyres)

Question 13

What was Hooke’s law?

Answer 13

The extension of an elastic object is directly proportional to the force

Question 14

What happens when the force is not directly proportional to the extension of an elastic object?

Answer 14

The elastic limit has been reached and exceeded

Question 15

What s the resultant force?

Answer 15

A single force that can replace many forces. It shows the acceleration and the direction

Question 16

The ___ the mass of an object, the __ the acceleration for the same force

Answer 16

The bigger the mass of an object, the less the acceleration for the same force

Question 17

The ___ the force on an object, the ___ the acceleration for the same mass

Answer 17

The bigger the force on an object, the bigger the acceleration for the same mass

Question 18

How to work out kinetic energy from braking force and braking distance?

Answer 18

Kinetic energy= braking force x braking distance

Question 19

What is the unit for gravitational potential energy?

Answer 19

Joules (J)

Question 20

How to work out gravitational potential energy?

Answer 20

mass x gravitation field x change in height

Question 21

How to calculate momentum?

Answer 21

P (momentum) = mass x velocity

Question 22

What are the units for momentum?

Answer 22

kg/m/s

Question 23

What is the conservation of momentum?

Answer 23

Total momentum before a collision is equal to the total momentum after a collision

Question 24

What is needed to change momentum?

Answer 24

Force

Question 25

What happens (the longer the time period of which this momentum change happens)

Answer 25

The smaller the force needed

Question 26

How do crumple zones keep you safe in a car crash?

Answer 26

They're at the front and back of the car and crumple upon impact. - The cars kinetic energy is converted into other forms of energy by the car body as it changes shape - Crumple zones increase the impact time, decreasing the force produced by the change in momentum

Question 27

How do side impact bars keep you safe in a car crash?

Answer 27

They are strong metal tubes fitted into car door panels -They help direct the kinetic energy of the crash away from the passengers to other areas of the car, such as crumple zones

Question 28

How to seat belts keep you safe in a car crash?

Answer 28

Seat belts stretch slightly, increasing the time taken for the wearer to stop moving. This reduces the forces acting on the chest. Some of the kinetic energy is absorbed by the seat belt stretching.

Question 29

How do air bags keep you safe in a car crash?

Answer 29

They slow you down more gradually and prevent you from hitting a hard surface such as the dashboard or steering wheel

Question 30

What happens when a driver brakes?

Answer 30

-The driver applies the breaks and the velocity decreases to 0m/s. No kinetic energy -The brake touches the wheel and creates friction between the brake and the wheel. The kinetic energy is converted into heat energy -Temperature of the brake increases as the velocity of the car decreases

Question 31

What happens in regenerative braking?

Answer 31

As the car breaks the kinetic energy of the car is converted to electrical energy and stored in the battery -The stored energy is later used in the electric motors of hybrid cars

Question 32

Advantages of regenerative braking

Answer 32

- Less energy wasted than in conventional braking - Less petrol is needed therefore lower CO2 emissions - Very useful in city traffic where cars brake frequently

Question 33

Disadvantages of regenerative braking

Answer 33

-More expensive than conventional braking systems -Less useful for motorway driving where braking is less frequent Adds weight to car

Question 34

Describe the stages of terminal velocity

Answer 34

- Initially, the only force acting on a falling object if weight/gravity (The object is at it's greatest acceleration) - After a short while, as the speed increases so does the drag/ air resistance (The acceleration decreases) - The force balance out. The drag equals the weight. (Meaning terminal velocity is 0/ zero)

Question 35

What part of the atom was thought of as the 'plum pudding?'

Answer 35

The positive part of the atom (mass of positive charge)

Question 36

Most of the alpha particles go straight through the gold foil

Answer 36

Most of the atom is empty

Question 37

Some alpha particles are deflected through a big angle

Answer 37

The nucleus has a large positive charge

Question 38

Only a very small number of alpha particles rebound backwards

Answer 38

The nucleus of the atom is very small