Work and energy

Work done by a force perpendicular to the displacement is:

• 1 Negative
• 2 Infinite
• 3 Zero
• 4 Maximum

A force of 10 N at 60 degrees to the displacement moves a body 4 m. The work done is:

• 1 34.6 J
• 2 40 J
• 3 20 J
• 4 10 J

The work energy theorem states that the net work done equals the change in:

• 1 Power
• 2 Momentum
• 3 Kinetic energy
• 4 Potential energy

A 1000 W motor lifts a load in 10 s. How much work does it do?

• 1 100 J
• 2 10000 J
• 3 10 J
• 4 1000 J

The escape speed from Earth is about:

• 1 11.2 km/s
• 2 1.1 km/s
• 3 112 km/s
• 4 3 x 10⁵ km/s

Power is measured in:

• 1 Pascals
• 2 Watts
• 3 Joules
• 4 Newtons

A conservative force is one for which the work done:

• 1 Depends on the path
• 2 Is always zero
• 3 Is always negative
• 4 Is independent of the path

The kinetic energy of a body becomes four times when its speed is:

• 1 Unchanged
• 2 Tripled
• 3 Halved
• 4 Doubled