Physics - Energy

Question 1

What are four different types of energy stores?

Answer 1

Possible answers: Thermal, Kinetic, Gravitational Potential, Elastic Potential, Chemical, Magnetic, Electrostaic, Nuclear

Question 2

Describe how energy is transferred as a ball falls to the ground?

Answer 2

A ball dropped from a height is accelerated by gravity. The gravitational force does work. It causes energy to be transferred from the ball’s gravitational potential energy store to its kinetic energy store.

Question 3

What is the equation for calculating the amount of energy in an objects kinetic energy store?

Answer 3

Kinetic energy = 1/2 x Mass x Speed squared

Question 4

What is work done?

Answer 4

Work done is just another way of saying energy transferred

Question 5

What happens to energy after it is used?

Answer 5

Energy is never used up it is only transferred between different energy stores and different objects.

Question 6

What is kinetic energy?

Answer 6

Any object or particle that is in motion (moving). An object gains kinetic energy when its speed increases, it loses it when its speed decreases.

Question 7

What is Gravitational potential energy?

Answer 7

Gravitational potential energy is the energy stored in an object as the result of its vertical position or height. The energy is stored as the result of the gravitational attraction of the Earth for the object.

Question 8

What is the eqation for gravitational potential energy?

Answer 8

G.P.E = Mass x Gravitational field strength x Height

Question 9

If energy is transferred to an object’s kinetic energy store what happens to its speed

Answer 9

The speed of the object increases

Question 10

What is the definition of the specific heat capacity of a material?

Answer 10

Specific heat capacity is the amount of energy needed to raise the temperature of 1 kg of a substance by 1 ‘C

Question 11

What is the equation that relates energy transferred to specific heat capacity?

Answer 11

Change in thermal energy = Mass x Specific heat capacity x Temperature change

Question 12

What is the conservation of energy principle?

Answer 12

Energy can be transferred usefully, stored, or dissipated, but can never be created or destroyed.

Question 13

What is power?

Answer 13

Power is the rate of energy transfer or the rate of doing work

Question 14

What are the two different equations that can be used for power?

Answer 14

Power = Energy transferred/time, Power = Work done/time

Question 15

What are the units power is measured in?

Answer 15

Watts

Question 16

What is dissipated energy referred to as and why?

Answer 16

Dissipated energy is sometimes referred to as wasted energy, this is because the energy is not being stored in a useful way.

Question 17

What is conduction?

Answer 17

Conduction is the process where vibrating particles transfer energy to neighbouring particles.

Question 18

What is convection?

Answer 18

Convection is where energetic particles move away from the hotter to cooler regoins.

Question 19

What is the efficiency of an energy transfer?

Answer 19

The efficiency of a device is the proportion of the energy supplied that is transferred in useful ways. The efficiency can be calculated as a decimal or a percentage.

Question 20

What are the two different equations that can be used to calculate the efficiency of an energy transfer?

Answer 20

Efficiency = Useful output energy transfer/Total input energy transfer, Efficiency = Useful power output/Total power input

Question 21

What are four renewable energy resources and nonrenewable energy resources?

Answer 21

Nonrenewable: Oil, Natural gas, Coal, and Nuclear energy
Renewable: Solar energy, Wind energy, Hydro energy, Geothermal energy