Forces & Energy

A skier walks from the bottom of a ski slope to the top and gains 10 000 J of gravitational potential

energy.

She skis down the slope. At the bottom of the slope, her kinetic energy is 2000 J.

How much energy is dissipated in overcoming friction and air resistance as the skier moves down

the slope?

• 2000 J

• 8000 J

• 10 000 J

• 12 000 J

A coal-fired power station generates electricity. Coal is burnt and the energy released is used to boil water. The steam from the water makes the generator move and this produces electricity.

Which words are used to describe the energy stored in the coal and the energy of the moving generator?

• coal : chemical, generator : hydroelectric

• coal :chemical, generator : kinetic

• coal : geothermal, generator : hydroelectric

• coal : geothermal, generator : kinetic

Which energy source is one that is used to boil water to make steam in power stations?

• energy from tides

• energy from waves

• hydroelectric energy

• nuclear energy

Which energy source is renewable and reliably available at all times?

• coal

• geothermal

• nuclear

• wind

Which quantities are measured in the same unit?

• energy, power and work

• energy and power, but not work

• energy and work, but not power

• power and work, but not energy

A person in a factory has to lift a box on to a shelf.

Which action involves the person doing the least amount of work?

• lifting the box quickly to the high shelf

• lifting the box slowly to the high shelf

• lifting the box to the low shelf first then lifting it to the high shelf

• lifting the box to the low shelf instead of to the high shelf

A ball is dropped on to a hard surface and bounces. It does not bounce all the way back to where it started, and so has not regained all of its original gravitational potential energy.

Which statement accounts for the loss of gravitational potential energy?

• Energy was destroyed as the ball hit the ground.

• Energy was destroyed as the ball travelled through the air.

• The chemical energy and elastic energy of the ball have increased.

• The internal (heat) energy of the ball and its surroundings has increased.

Which energy resource is used to boil water to generate electricity?

• hydroelectric

• nuclear fission

• tides

• waves

A cyclist travels down a hill from rest at point X, without pedalling.

The cyclist applies his brakes and the cycle stops at point Y.

Which energy changes have taken place between X and Y?

• gravitational potential → kinetic → thermal (heat)

• gravitational potential → thermal (heat) → kinetic

• kinetic → gravitational potential → thermal (heat)

• kinetic → thermal (heat) → gravitational potential

Which energy transfer takes place when a matchstick burns?

• chemical to thermal

• chemical to nuclear

• nuclear to chemical

• thermal to chemical