An electric motor raises a load of 0.2 kg, at a constant speed, through a vertical distance of 3.0 m in 2 s. If the acceleration power stations and thermal power stations, alternators produce electricity

A. 0.3 B. 1.2

C. 3.0 D. 6.0

Which of the following energy change involves frictional force?

A. Chemical energy to heat energy

B. Kinetic energy to heat energy

C. Potential energy to sound energy

D. Chemical energy to kinetic energy

Which one of the following statements about power stations is not true?

A. Hydroelectric power stations use water to drive turbines

B. In a power station, turbines drive generators

C. Electricity from thermal power stations differs from that produced in hydroelectric power stations

D. In hydroelectric power stations and thermal power stations, alternators produce electricity.

An object is falling freely from a height x. After it has fallen a height, it will possess :

A. Only potential energy

B. Only kinetic energy

C. Half potential and half kinetic energy

D. Less potential and more kinetic energy

The commercial unit of energy is:

A. Watt B. Watt-hour

C. Kilowatt-hour D. Kilowatt