Chapter 6: Energy, Work and Power

Question 1

What is energy?

Answer 1

The capacity to do work

Question 2

What is the SI unit of energy?

Answer 2

Joule(J)

Question 3

What are the types of energy?

Answer 3

1. Kinetic energy

2. Potential energy

Question 4

What is kinetic energy? What can it be used for?

Answer 4

The energy of a body due to its motion

Kinetic energy can be used to do works

Question 5

What is potential energy?

Answer 5

The energy stored in a system

Question 6

What are the types of potential energy?

Answer 6

1. Chemical potential energy
   2 Elastic potential energy
2. Gravitational potential energy

Question 7

What is chemical potential energy?

Answer 7

The energy stored in a substance due to the position of the atoms and electrons in the structure

Question 8

What are the sources of chemical potential energy?

Answer 8

1. Food
2. Fossils
3. Batteries

Question 9

What is elastic potential energy?

Answer 9

The energy of a body due to its elastic deformation

Question 10

What is gravitational potential energy?

Answer 10

The energy stored in a body due to its height from the ground

Question 11

What are other forms of energy?

Answer 11

1. Electrical energy
2. Light
3. Thermal energy
4. Nuclear energy

Question 12

What is electrical energy?

Answer 12

The energy of an electric charge due to its motion and position

Question 13

What is light?

Answer 13

An electromagnetic wave that is visible to the eye

Question 14

What is light made up of?

Answer 14

Electric fields

Magnetic fields

Question 15

What are some examples of natural sources of light?

Answer 15

Sun

Fires

Question 16

What are some examples of artificial sources of light?

Answer 16

Incandescent bulbs
Fluorescent lamps
Light-emitting diodes (LED)

Question 17

What is thermal energy? Transferred from?

Answer 17

The energy stored in a body due to its temperature

Thermal energy is transferred from the hotter body to the colder body

Question 18

What is nuclear energy?

Answer 18

The energy released during a nuclear reaction

Question 19

What are the types of nuclear energy?

Answer 19

Nuclear fission

Nuclear fusion

Question 20

What is nuclear fission?

Answer 20

A heavier nucleus splits up into two or more lighter nucleus

Question 21

What is nuclear fusion?

Answer 21

Two or more lighter nuclear fuse together to form a heavier nucleus

Question 22

What is the Principle of Conservation of Energy?

Answer 22

The Principle of Conservation of Energy states that energy cannot be created or destroyed, but can be converted from one form to another. The total energy in an isolated system is constant

Question 23

What is work done?

Answer 23

The product of the force and the distance moved by the object in the direction of the force

Question 24

What is the formula of work done?

Answer 24

W = F x s
Where
W = work done (J)
F = constant force (N)
s = distance (m)

Question 25

What is the SI unit of work done?

Answer 25

joule(J)

Question 26

Relationship of work relating to energy and force

Answer 26

Energy is needed to do work. Work is done when an object moves under the influence of a force

Question 27

What are examples of work?

Answer 27

1. Moving a box across the floor | 2. Climbing a flight of stairs

Question 28

What is the formula of kinetic energy?

Answer 28

``` Ek = 1/2mv^2 Ek = kinetic energy (J) m = mass (kg) v = speed (m s^-1) ```

Question 29

What is the formula of gravitational potential energy?

Answer 29

``` Ep = mgh Ep = gravitational potential energy (J) m = mass (kg) g = gravitational field strength (m s^-2) h = height (m) ```

Question 30

What is power?

Answer 30

The rate or work done or rate of energy conversion

Question 31

What is the formula of power?

Answer 31

``` P = W / t = E / t P= Power (W) W = Work done (J) E = Energy converted (J) t = time taken (s) ```

Question 32

What is the SI unit of power? What is 1W equal to?

Answer 32

Watt (W) | 1W = 1J s^-1