Energy - energy stores and transfers

Question 1

kinetic energy

Answer 1

energy stored in moving objects

Question 2

gravitational potential energy

Answer 2

energy stored due to an object’s position above the ground

Question 3

thermal energy

Answer 3

energy stored in a substance due to the motion of its particles

Question 4

chemical energy

Answer 4

energy stored in chemical bonds (e.g. in food or fuel)

Question 5

magnetic energy

Answer 5

energy stored in magnetic fields

Question 6

nuclear energy

Answer 6

energy stored in the nucleus of atoms

Question 7

how is GPE transferred to KE

Answer 7

Gravitational Potential Energy is transferred into Kinetic Energy when an object falls

Question 8

Elastic Potential Energy

Answer 8

energy stored in something that is stretched or compressed

Question 9

what is the law of conservation energy

Answer 9

energy cannot be created or destroyed but it can transfer between different energy stores

Question 10

what is the gravitational field strength on the surface of earth

Answer 10

9.8 N/kg

Question 11

what is the GPE equation

Answer 11

GPE = m x g x h (GPE = mass x gravitational field strength x height)

Question 12

what is the kinetic energy equation

Answer 12

Ek = 1/2 x m x v2 (Kinetic energy = 1/2 x mass x (velocity)2)

Question 13

when a ball drops what happens

Answer 13

starts with GPE. When the ball drops, GPE decreases. This is because GPE depends on height, and as the ball falls, its height above the ground decreases. The lost GPE is transferred into kinetic energy as the ball speeds up during its fall.

Question 14

name the 8 energy stores

Answer 14

• thermal
• GPE
  -Elastic potential
  -Magnetic
  -chemical
  -electrostatic
  -nuclear
  -kinetic

Question 15

give the 4 ways energy can be transferred

Answer 15

mechanically, electrically, through heating via infrared radiation, via light or sound waves

Question 16

what two stores of energy does thermal energy include

Answer 16

kinetic, potential

Question 17

electrostatic

Answer 17

the energy stored when repelling charges have been moved closer together or when attracting charges have been pulled further apart

Question 18

what is dissipated energy

Answer 18

energy that is lost to the surroundings

Question 19

what is waste energy

Answer 19

energy that is not used by the device for its desired purpose e.g. heat energy given off by a light bulb

Question 20

what are the units for kinetic energy

Answer 20

Joules (J)

Question 21

what are the units for mass when calculating kinetic energy

Answer 21

Kg

Question 22

what are the units for velocity when calculating kinetic energy

Answer 22

metres per second

Question 23

what is gravity

Answer 23

an invisible force that pulls objects towards each other

Question 24

what is weight

Answer 24

an object’s weight is the force acting on that object due to gravity

Question 25

what is gravitational field strength

Answer 25

the strength of a gravitational field around an object

Question 26

which two factors affect the strength of gravitational attraction between two objects

Answer 26

-the masses of the object -the distance between them

Question 27

what happens to the GPE of an object as it falls

Answer 27

decreases

Question 28

what happens to the KE of a ball that rolls down a hill

Answer 28

the kinetic store of the ball will increase as the GPE is transferred to the kinetic store

Question 29

a ball is thrown upwards in the air. what happens to the GPE and KE stores of the ball

Answer 29

GPE increases, KE decreases

Question 30

what happens to the KE of a ball as it falls through air

Answer 30

increases

Question 31

to calculate the velocity of an object at the bottom of a fall, you need to...

Answer 31

rearrange the equation of mgh= 1/2mv2 ---> gh = 1/2v2 -----> v = square root of 2gh