Energy and Work

Question 1

Recall and apply law of conservation of energy

Answer 1

Energy can’t be destroyed or created but may be transformed from one type to another

Question 2

Why are energy transformations not 100% efficient

Answer 2

Some energy may be transferred into the surrounding environment as unwanted heat, sound or light

Question 3

Energy transformations in everyday life

Answer 3

A hairdryer uses 1200Joules. 600Joules for drying hair. Wasted sound energy.

Question 4

Examples of conversion of electrical energy in light

Answer 4

Electrical energy turns into light to illuminate rooms

Question 5

Examples of conversion of electrical energy in movement

Answer 5

Electrical energy to make fan blades spin for breeze

Question 6

Examples of conversion of electrical energy in sound

Answer 6

Electrical energy creates sound waves for music or voice

Question 7

What is energy

Answer 7

Energy is the ability to do work

Question 8

How to calculate work done

Answer 8

You calculate work done by Force x distance (W=Fd)

Question 9

Gravitational potential energy

Answer 9

The energy an object has due to its position above earth due to its height

Question 10

Electrical potential energy

Answer 10

The energy that is needed to move a charge against an electric field

Question 11

Chemical potential energy

Answer 11

The energy stored in the chemical bonds of substance

Question 12

Elastic potential energy

Answer 12

Energy stored as a result of applying a force to deform an elastic object

Question 13

Kinetic energy

Answer 13

Energy possessed by objects that are moving

Question 14

Thermal energy

Answer 14

Energy that causes objects to gain temperature

Question 15

Light energy

Answer 15

Energy that may be release, for example, when an object is hot or by a nuclear reaction by a star

Question 16

Sound energy

Answer 16

Energy that is carried by the air in a room and detected by the ear

Question 17

Nuclear potential energy

Answer 17

Energy stored in nucleus of atoms that can release energy slowly like in a reactor or quickly like a nuclear explosion.

Question 18

Renewable energy

Answer 18

They can be easily renewed at the rate it is used

Question 19

Non Renewable energy

Answer 19

Cannot be regenerated

Question 20

Renewable energy examples

Answer 20

Geothermal, solar, hydroelectric

Question 21

non Renewable energy examples

Answer 21

Coal, oil, uranium

Question 22

When is work done

Answer 22

When the point of a force is applied and it moves in the direction of the force.

Question 23

How to calculate the work done

Answer 23

Multiplying the force and distance it moves (W=Fd)

Question 24

The unit for work and energy

Answer 24

Joule

Question 25

How can work be done to increase Kinetic energy

Answer 25

Pushing or pulling to speed up the object

Question 26

How can work be done to increase GPE

Answer 26

Lifting the object upward

Question 27

How can work be done to increase EPE

Answer 27

Stretching or compressing and elastic object like a spring