What is the law of conservation of energy?

• Energy can never be destroyed, only ever transferred or stored

• Energy is always the same

• Energy can never be destroyed, only ever used or wasted

• We must conserve energy to save the planet

For a swinging pendulum the energy changes are...

• From GPE to kinetic

• From GPE to chemical

• From Kinetic to chemical

• From Elastic Potential to kinetic

Wasted energy is...

• like wasted time

• Energy that is not useful

• always lost as heat

• Energy that is lost in the process of production.

In a closed system the total net energy of the system...

• Always increases

• Stays the same

• Always decreases

Few systems are closed, a pendulum's energy is damped by the air and lost in the form of

• Elastic energy

• Kinetic energy

• Heat energy dissipated to the surroundings

• Gravitational potential

What is the Gravitational potential energy of a an object with a mass of 4kg at a height of 25m?

• 98J

• 100J

• 980J

• 1000J

An object has a GPE of 10 kJ, if the mass is 50 kg what is the height?

• 200 m

• 20 m

• 4,900 km

• 0.020 m

The mass of one rider on a slide is 62.5 kg. The height of the slide is 16.0 m.

Calculate the gravitational potential energy of the rider at the top of the slide.

• 1600 J

• 980 J

• 1200 J

• 9800 J

 At the bottom of the slide the speed of the rider from the previous question is 12 m/s.
The mass of the rider is 62.5 kg.
Calculate the kinetic energy of the rider at the bottom of the slide.

• 4500 J

• 3800 J

• 9000 J

• 375 J

The height of some stairs was 1.7 m. A girl of mass 50 kg climbs them, what is her gain in GPE?

• 86 J

• 338 J

• 833 J

• 896 J