1.7 Energy, Work and Power

The S.I. unit for energy is ___________

The Principle of Conservation of Energy states that

'Energy cannot be _________ nor _________ but is ________ from one store to another, it is always ________.

• created, destroyed, transferred, conserved

• transferred, conserved, created, destroyed

The diagram shows a battery-operated motor lifting a block of wood at constant speed. What is the overall energy change taking place?

• chemical energy to gravitational potential energy

• gravitational potential energy to electrical energy

• gravitational potential energy to kinetic energy

• kinetic energy to gravitational potential energy

A boulder falls off a cliff. As it falls, its gravitational potential energy __________ and its kinetic energy __________. The thermal energy produced also _________.

• decreases, increases, increases

• increases, decreases, decreases

• decreases, increases, decreases

• increases, decreases, increases

A 2 kg mass is moving at constant speed of 20 m/s.  What is the kinetic energy of the mass?

• 10 J

• 40 J

• 200 J

• 400 J

There is a bell at the top of a tower that is 45 m high. How much gravitational potential energy does it possess if it has a mass of 20 kg? (Take g = 9.8 N/kg)

• 450 J

• 900 J

• 8820 J

• 10 200 J

The formula for work done is

• force x distance

• force ÷ distance

• mass x distance

• mass ÷ distance

A 300 N force is applied to a box to move it up a ramp, as shown. How much work is done by the force when moving the box from X to Y?

• 900 J

• 1200 J

• 1500 J

• 3000 J

Which power stations all rely on renewable sources of energy?

• hydroelectric, oil-fired, solar power stations

• hydroelectric, solar, wind power stations

• hydroelectric, oil-fired, wind power stations

• oil-fired, wind, solar power stations

Coal is burned as fuel to heat water in a boiler, producing steam. The steam drives a turbine, which is connected to an electric generator. In which order do the major energy transformations take place?

• chemical energy → thermal energy → electrical energy → kinetic energy

• chemical energy → thermal energy → kinetic energy → electrical energy

• thermal energy → chemical energy → electrical energy → kinetic energy

• thermal energy → chemical energy → kinetic energy → electrical energy