Work, Energy and Power

The law of conservation of energy states that:

1. Energy can be created but not destroyed
2. Energy can neither be created nor destroyed
3. Energy is always lost
4. Only kinetic energy is conserved

The efficiency of a machine is defined as:

1. Output work/Input work
2. Input work/Output work
3. Force x distance
4. Energy x time

The energy stored in a stretched spring is:

1. Kinetic energy
2. Chemical energy
3. Elastic potential energy
4. Thermal energy

When the force acting on an object is perpendicular to its displacement, the work done is:

1. Maximum
2. Minimum but positive
3. Zero
4. Negative

A body at rest has:

1. Maximum kinetic energy
2. Zero kinetic energy
3. Infinite kinetic energy
4. Negative kinetic energy

Mechanical energy is the sum of:

1. Heat energy and light energy
2. Kinetic energy and potential energy
3. Electrical energy and chemical energy
4. Nuclear energy and thermal energy

The SI unit of power is:

1. Joule
2. Watt
3. Newton
4. Erg

Which of the following is a conservative force?

1. Frictional force
2. Gravitational force
3. Air resistance
4. Viscous force

If the velocity of an object is doubled, its kinetic energy becomes:

1. Two times
2. Three times
3. Four times
4. Eight times

The rate of doing work is called:

1. Energy
2. Force
3. Power
4. Momentum

The work-energy theorem states that:

1. Work done is equal to change in kinetic energy
2. Work done is equal to change in potential energy
3. Energy is always destroyed
4. Power is equal to force

The energy possessed by an object due to its position is called:

1. Kinetic energy
2. Potential energy
3. Mechanical energy
4. Thermal energy

Kinetic energy of an object depends on:

1. Mass only
2. Velocity only
3. Mass and velocity
4. Force only

The SI unit of work is:

1. Newton
2. Joule
3. Watt
4. Pascal

The work done by a force is maximum when the angle between force and displacement is:

1. 0°
2. 45°
3. 90°
4. 180°