Chapter 4

Question 1

Define Joule

Answer 1

1 Joule of work is done when a force of 1 N moves an object 1 m in the direction of the force

Question 2

Work =

Answer 2

distance x force
energy transformed
power x time

Question 3

Types of potential energy

Answer 3

Gravitational
Elastic
Chemical
Electrical
Nuclear

Question 4

The Law of Conservation of Energy

Answer 4

Energy cannot be created or destroyed but it can change from one form to another

Question 5

gravitational potential energy =

Answer 5

PE = mgh

Gravitational potential energy = mass x g x height

Question 6

kinetic energy =

Answer 6

KE = 1/2 mv^2

kinetic energy = 1/2 x mass x velocity^2

Question 7

efficiency =

Answer 7

useful (power or energy) output / total (power or energy) input

Question 8

power =

Answer 8

power = work done/time taken
power = energy transformed/ time taken

Question 9

How is nuclear energy produced

Answer 9

Splitting uranium atoms (nuclear fisson)

Question 10

Define Watt

Answer 10

A power of 1 Watt means that work is being done, or energy is being transformed at a rate of 1 J/second

Question 11

Why does the sun radiate energy?

Answer 11

Nuclear fusion reactions happen in its core, releasing energy