Conservation of Energy

Question 1

Name 6 different types of energy stores.

Answer 1

Magnetic, Chemical, Nuclear, Thermal, Electrical, Elastic, Gravitational, Kinetic, Electrostatic

Question 2

Fill in the blanks: Energy can be _______ but energy cannot be _______ or _______

Answer 2

Energy can transferred but it cannot be created or destroyed.

Question 3

What is energy measured in?

Answer 3

Joules (J)

Question 4

If a roller coaster is at the top of the ride and is about to go downhill. _______ type of energy will be transferred into _______ type of energy

Answer 4

Gravitational energy will be transferred into kinetic energy.

Question 5

Where did all the energy in the universe come from?

Answer 5

The big bang.

Question 6

How do we calculate gravitational potential energy?

Answer 6

Mass (KG) * Height (M) * Gravitational Field Strength (N/KG) = Gravitational potential energy.
NOTE : The gravitational field strength is usually 10 unless the exam says otherwise.

Question 7

Work out this question:
A cricketer throws a ball of mass 0.16 kg upwards. It falls back down to the ground from a height of 4.0 m. Calculate the amount of energy transferred. (Gravitational field strength, g = 10 N/kg.)

Answer 7

6.4 Joules (J)

Question 8

How do we calculate kinetic energy?

Answer 8

kinetic energy (J) = 0.5 × mass (kg) × (speed)^2 (m/s)

Question 9

Work out this question:

A racecar has a mass of 500 kg. Calculate its kinetic energy when it travels at 60 m/s.

Answer 9

900,000 Joules (J)
or 900 (kJ)

Question 10

What is the formula for efficiency?

Answer 10

( Useful energy / Total energy ) * 100

Question 11

What are two ways to eliminate wasted energy?

Answer 11

Lubricate mechanical parts and put wasted energy to good use.