physics test

Question 1

Energy

Answer 1

The ability to make changes happen

Question 2

Potential energy

Answer 2

stored energy

Question 3

chemical energy

Answer 3

energy stored within the chemical bonds of a substance

Question 4

nuclear energy

Answer 4

energy stored within the nucleus of an atom

Question 5

sound energy

Answer 5

energy that travels as vibrating waves that can be heard.

Question 6

electrical energy

Answer 6

the energy possessed by moving charged particles

Question 7

gravitational potential energy

Answer 7

the stored energy an object has due to its position above the earth

Question 8

thermal energy

Answer 8

a measure of the total kinetic energy possessed by particles in a substance

Question 9

kinetic energy

Answer 9

the energy possessed by moving objects

Question 10

light energy

Answer 10

a form of energy that is visible

Question 11

2 factors that affect kinetic energy

Answer 11

Mass and speed. More mass = more kinetic energy
More speed= more kinetic energy

Question 12

how to calculate kinetic energy

Answer 12

Ek (J)=1/2 x m (mass - kg) v*2 (velocity, speed in metres per second),

Question 13

gravitational potential energy formula

Answer 13

Ep (J) = m (mass - kg) x g (gravity=9.81) x h (height - m)

Question 14

energy transfer

Answer 14

the flow of energy from one object to another

Question 15

energy transformation

Answer 15

the conversion of energy from one form to another

Question 16

energy transfer example

Answer 16

kicking a ball: your leg –l> the ball

Question 17

energy transformation example

Answer 17

turning on light: chemical energy –l> light energy

Question 18

energy flow diagram

Answer 18

An energy flow diagram shows how energy is transformed from one form to another. e.g. light/heat energy from the sun –l> chemical energy in food –l> kinetic energy during sports

Question 19

Law of conservation of energy

Answer 19

the law that energy can not be created or destroyed, only transferred/transformed from one type to another.

Question 20

energy efficiency

Answer 20

proportion of useful energy output compared to the energy input as a percentage

Question 21

how to calculate energy efficiency

Answer 21

(useful energy output/total energy input) x 100 = efficiency %

Question 22

Thermal energy

Answer 22

The total measure of kinetic energy within a substance. measures mass and speed of the particles.

Question 22

what is thermal energy measured in?

Answer 22

Joules

Question 23

temperature

Answer 23

measures the speed of the particles within a substance. (℃)

Question 24

Temperature vs heat

Answer 24

temperature measures the speed of particles, while heat is the mass and speed.

Question 25

example of temp vs heat

Answer 25

a pool of water at 30℃ has more kinetic energy than a cup of water at 90℃.

Question 26

particle theory: all matter is made up of __________ that are _________. the movement is due to _________. the more _____, the faster the ____________ move.

Answer 26

All matter is made up of tiny particles that are always moving. The movement is due to heat energy. the more heat, the faster the particles move.

Question 27

Solids

Answer 27

solids are held in fixed positions and vibrate

Question 28

liquids

Answer 28

liquid particles are close but move around. take the shape of the container

Question 29

gases

Answer 29

Gases particles are spaced apart and move at very high speeeds, often colliding with each other and the walls of the containers.

Question 29

expansion

Answer 29

when a substance is heated, the particles gain kinetic energy, move faster, and the distance between them increases. this causes the substance to expand.

Question 30

contraction

Answer 30

when a substance is cooled, the particles lose kinetic energy, move slower, the distance between them decreases, causing the volume to decrease.

Question 30

ex. of chemical potential energy

Answer 30

food

Question 30

ex. of gravitational potential energy

Answer 30

bird in a tree

Question 30

ex. of nuclear energy

Answer 30

can produce electricity

Question 31

Law of thermodynamics

Answer 31

it is not possible to convert one form of energy to another with 100% efficiency. Some energy is always lost as waste heat due to friction or other inefficiencies