P2b Topic 4 - Momentum, Energy, Work and Power

Question 1

Braking distance is affected by 4 main factors

Answer 1

A. How fast you’re going.
B. The mass of your vehicle.
C. How good your breaks are.
D. How good the grip is.

Question 2

Momentum (kg m/s) =

Answer 2

Mass (kg) TIMES BY Velocity (m/s)

Question 3

Momentum before =

Answer 3

Momentum after

Question 4

Force (N) =

Answer 4

Change in momentum (kg m/s) DIVIDED BY time

Question 5

When a force moves an object,

Answer 5

Energy is transferred and work is done

Question 6

Crumple zones crumple on impact,

Answer 6

Increasing the time taken for the car to stop.

Question 7

Seat belts stretch slightly,

Answer 7

Increasing the time taken for the wearer to stop. This reduces the force acting on the chest.

Question 8

Air bags

Answer 8

Slow you down more gradually.

Question 9

Work done =

Answer 9

Force TIMES distance moved in the direction of the force

Question 10

Power=

Answer 10

Work done DIVIDED BY time taken

Question 11

Kinetic energy =

Answer 11

1/2 TIMES mass TIMES velocity SQUARED

Question 12

Initial kinetic energy=

Answer 12

Work done by breaks to stop vehicle

Question 13

Gravitational potential energy =

Answer 13

Mass TIMES gravitational field strength TIMES height

Question 14

Energy can never be created nor destroyed

Answer 14

• only transferred from one form to another.

Question 15

Kinetic energy gained =

Answer 15

Gravitational potential energy lost

Question 16

Thinking distance is affected by 2 main factors

Answer 16

A. Your reaction time - this is affected by tiredness, drugs, alcohol, old age.
B. How fast you’re going.