Chapter 6

Question 1

energy

Answer 1

exists in different forms and when something happens, it is likely be due to energy being transferred from one form to another. energy transfer is needed to enable people, computers machines and other devices to work and to enable processes and changes to occur

Question 2

kinetic energy

Answer 2

energy of a moving object

Question 3

gravitational energy

Answer 3

energy something gains when you lift it up, and which it loses when it falls

Question 4

elastic energy

Answer 4

the energy of a stretched spring or elastic band (also known as strain energy)

Question 5

chemical energy

Answer 5

energy contained in a chemical substance

Question 6

nuclear energy

Answer 6

the energy contained within a nucleus of an atom

Question 7

internal energy

Answer 7

the energy stored in a hot object is called internal energy . the atoms of a hot object jiggling rapidly about, they have a lot of energy

Question 8

thermal heat

Answer 8

this is energy traveling from a hotter object to a cooler one. it is transferred by conduction, convection or radiation

Question 9

other forms of energy

Answer 9

light and electromagnetic energy and sound energy

Question 10

energy stores

Answer 10

-kinetic
-gravitational potential
-chemical
-nuclear
-strain
internal

Question 11

energy transfers

Answer 11

-electrical
-thermal
-light
sound

Question 12

energy being transferred

Answer 12

by a force: lift something, force it to move
by heating: no matter how good insulation, heat goes from hot object to cooler surroundings
By radiation: energy transferred from sun to earth, electromagnetic radiation
by electricity: an electrical current is a convenient way of transferring energy from place to place

Question 13

law of conservation of energy

Answer 13

energy cannot be destroyed, only can change form

-the total amount of energy before and after is constant

Question 14

conservation of energy in multiple stages

Answer 14

many processes involve several steps before energy ends up in final form
eg: chemical to electrical

Question 15

energy dissipation

Answer 15

when energy is transferred from one to another form, energy is lost in desired form or place (it ends up being dissipated usually in form of heat, energy light and sound)

• most common waste = heat
• wasted energy can harm environment, waste limited resources and cost money

Question 16

energy efficiency

Answer 16

when energy is transformed =some energy is wasted and transferred away from system usually in the form of heat or waves (light and sound)

Question 17

efficient system

Answer 17

• energy is transferred and waste energy is a form usually unwanted
• is a system where most energy is going into that system is in a form wanted
• eg: LED because most electrical energy (90%) ends up as light

Question 18

inefficient system

Answer 18

is one which most energy ends up in forms not wanted

Question 19

efficiency equation

Answer 19

useful energy(or power) output /
energy (or total power) input
x100

Question 20

gravitational potential energy calculations (g.p.e)

Answer 20

gravitational energy = of an object us the energy it has due to its height in the gravitational field

• object lift =increase \
• falls = decreases

G.P.E = Mass x gravity x Height
OR
WEIGHT x HEIGHT

Question 21

kinetic energy equation

Answer 21

1/2 x mass x speed^2

k.e = 1/2mv^2

Question 22

Weight si unit

Answer 22

Newton’s

N