Energy and Momentum

Question 1

What is the stopping distance?

Answer 1

The sum of the thinking and braking distances.

Question 2

What is thinking distance affected by?

Answer 2

1. Speed

2. Alertness

Question 3

What is thinking distance?

Answer 3

The distance the vehicle travels during the driver’s reaction time.

Question 4

What is braking distance affected by?

Answer 4

1. Speed
2. Brakes
3. Tyres
4. Grip

Question 5

What is breaking distance?

Answer 5

The distance the vehicle travels under the braking force.

Question 6

What is work?

Answer 6

When a force moves an object through a distance, work is done and energy is transferred.

Question 7

What is work measured in?

Answer 7

Joules, J.

Question 8

What is the formula for work?

Answer 8

Work done = force x distance

J = N x m

Question 9

What is gravitational potential energy?

Answer 9

Energy due to vertical position in a gravitational field.

Question 10

What is the gravitational potential energy formula?

Answer 10

GPE = mass x gravity x height
J = kg x N/kg x m

Question 11

What is kinetic energy?

Answer 11

Energy due to movement.

Question 12

What is the formula for kinetic energy?

Answer 12

KE = 1/2 x mass x speed^2
J = 1/2 x kg x m/s^2

Question 13

What do falling objects convert what into?

Answer 13

Potential energy into kinetic energy.

Question 14

What is the formula for work done by brakes?

Answer 14

1/2 x m x v^2 = F x d

1/2 x kg x m/s^2 = N x m

Question 15

Why do meteors and space shuttles entering the atmosphere burn up?

Answer 15

Friction with particles in the atmosphere.

Question 16

What happens when work is done to an elastic object?

Answer 16

The energy is stored by the object as elastic potential energy.

Question 17

What is the limit of proportionality?

Answer 17

The maximum force that an elastic object can take and still extend proportionally.

Question 18

What is the formula for spring extension?

Answer 18

Force = spring constant x extension
N = N/m x m

Question 19

What is power?

Answer 19

The rate at which work is done.

Question 20

What is the formula for power?

Answer 20

Power = Energy transferred / time
J/s = J / s

Question 21

What is one watt?

Answer 21

One joule of energy transferred per second.

Question 22

What are two ways to measure power output?

Answer 22

1. Timed run upstairs

2. Timed acceleration

Question 23

What does the timed run upstairs measure?

Answer 23

The potential energy gained.

Question 24

What does the timed acceleration measure?

Answer 24

The kinetic energy gained.