Energy transfers

Question 1

What is the formula for kinetic energy?

Answer 1

0.5 x mass x speed^2

Question 2

What is KE?

Answer 2

1/2 x M x v^2

Question 3

What is the formula for gravitational potential energy?

Answer 3

m x g x h

Question 4

What is the Law of Conservation of energy?

Answer 4

Energy can be stored or transferred between stores, and dissipated
+It can never be created or destroyed
+The total energy of a closed system has no net change

Question 5

Kinetic energy

Answer 5

Any moving object will have this.

Question 6

Chemical energy

Answer 6

anything that can release energy through a chemical reaction.

Question 7

Gravitational potential

Answer 7

Any object that is is in the air.

Question 8

Elastic potential

Answer 8

Anything stretched

Question 9

Electrostatic

Answer 9

Two charges that attract or repel each other

Question 10

Magnetic

Answer 10

Two magnets that attract or repel each other

Question 11

Nuclear

Answer 11

atomic nuclei release energy from this store in nuclear reactions

Question 12

What is the formula for efficiency?

Answer 12

Useful energy/total energy (j)

Question 13

When is energy useful?

Answer 13

When it is transferred from one store to a useful store.

Question 14

What is hydro-electricity?

Answer 14

+A renewable energy resource
+Involves flooding a valley by building a big dam
+Rainwater is caught and allowed out through turbines

Question 15

What are solar cells?

Answer 15

+Solar cells are made from materials that use energy transferred by light to create an electric current.
+It is often used in remote places & powers electric road signs and satellites.

Question 16

What are the advantages of solar cells?

Answer 16

+There’s no pollution.

+There are no running costs.

Question 17

What are the disadvantages of solar cells?

Answer 17

+Initial costs are high (very expensive)
+Most suitable for sunny countries, but can be used in cloudy countries like Britain.
+You can’t make solar power at night
+You can’t increase production when there’s extra demand.

Question 18

What are the advantages of hydro-electricity?

Answer 18

+No pollution
+An advantage is it can immediately respond to increased electricity demand - more water can be let through turbines to generate more electricity.
+Minimal running costs
+Generally a reliable energy source.

Question 19

What are the disadvantages of hydro-electricity?

Answer 19

• There is a big impact on environment due to flooding of valley and (possible) loss of habitat for some species.
• Initial costs are high