Energy

Question 1

Kinetic energy equation

Answer 1

Kinetic Energy
𝐸𝑘 = 1/2mv squared
Ek = 1/2 x mass x speed squared (m/s)

Question 2

Elastic potential equation

Answer 2

𝐸𝑒 = 1/2𝑘𝑒 squared
Ee = 1/2 x spring constant (N/m) x extension squared (m)

Question 3

Gravitational Potential Energy

Answer 3

Gravitational Potential Energy
𝐸𝑝 = mgh
Ep = mass x gravitational field strength (N/kg) x height

Question 4

specific heat capacity equation

Answer 4

Specific Heat Capacity
energy = mass × specific heat capacity × temperature change

Question 5

Power def + equation

Answer 5

Power
Power is defined as the rate at which energy is transferred or the rate at which work is done.

Power = energy transferred / time

Question 6

2 ways to reduce energy waste

Answer 6

Reducing energy waste:
- Lubrication
o Oil in a motor
o Reduces friction
o So less energy is lost (as heat) through friction
- Thermal Insulation
o Double Glazing
o Less useful thermal energy lost

Question 7

Efficiency equation

Answer 7

Efficiency = useful output / total input

Question 8

The efficiency of a system can be increased by…

Answer 8

1. Reducing waste output (lubrication, thermal insulation, etc.)
2. Recycling waste output (e.g. absorbing thermal waste and recycling as input
   energy)

Question 9

Non - renewable energy resources (2)

Answer 9

1. Fossil Fuels (coal, oil, gas)
2. Nuclear Fuel

Question 10

Renewable energy resources (7)

Answer 10

1. Biofuel
2. Wind
3. Hydro-electricity
4. Geothermal
5. Tidal
6. Solar
7. Water waves

Question 11

What kind of energy resources are used for large scale energy supplies?

Answer 11

Non-renewable energy is used more for large-scale energy supplies due to the large energy
output per kilogram of fuel

Question 12

two examples why renewable energy is less reliable

Answer 12

• Solar doesn’t work in bad weather or night
• Wind is only intermittent.

Question 13

3 main energy uses

Answer 13

Main Energy Uses
- Transport
- Electricity generation
- Heating

Question 14

The enviromental impacts of
1. extracting energy
2. using energy

Answer 14

extracting energy:
o Fossil fuels involve destroying landscapes
o Wind turbines can be considered an eyesore
using energy:
o Fossil fuels release harmful emissions
o Solar, wind directly create electricity with no emissions

Question 15

patterns and trends of energy use (3 points)

Answer 15

-During industrial revolution, fossil fuels became an important source of energy as it was easy
to mine, and provided a lot of energy
- Only recently has renewable energy become more suitable – technology has had to develop
a lot since industrial revolution to be able to harness such energy sources efficiently
- It is easier to use energy resources due to increasing pressure to cope with the public’s
increasing power demands but harder to solve environmental issues due to political, social,
ethical and economic considerations.

Question 16

Conservation of Energy

Answer 16

Conservation of Energy: The law that energy can be transferred, stored or
dissipated but never created or destroyed.