QUIZ 3 (TOPIC 4-WORK,ENERGY AND POWER)

The energy possessed by body due to its position is called

• kinetic energy
• potential energy
• nuclear energy
• electrical energy

The principle of conservation of energy state that

• In an isolated system, total energy is conserved.
• Kinetic energy is always equal to the potential energy
• The net work done on the system equals the change in kinetic energy
• Energy can be created and destroyed, it can only be transferred or changed from one form to another

What is the equation for power?

• P = Work/time
• P = Force/time
• P = Time/distance
• P = Time/Work

The work–kinetic energy theorem stated that

• work done on an object is equals to the change in its kinetic energy
• work done on an object comes from the kinetic energy.
• work and kinetic energy are the same thing.
• work and kinetic energy cannot co–exist at the same time

FIGURE shows an object placed on a table. It is observed that normal force, N and gravitational force, mg both do no work to the object. This is because

• W=Fs cos θ and θ is 90°, hence work is zero
• W=Fs cos θ and θ is 0°, hence work is zero
• W=Fs sin θ and θ is 90°, hence work is zero
• W=Fs sin θ and θ is 0°, hence work is zero

When a body slides against a rough horizontal surface, the work done by friction is

• positive
• zero
• negative
• constant

Which is the unit for work done?

• Nm−1
• W
• Ns
• J

Kinetic energy depends on the

• mass and height.
• mass and speed.
• height and speed.
• mass and gravity

On a plot of graph force against displacement (F-s), what represents the work done by the force F?

• the area under the curve.

• the slope of the curve.

• the length of the curve.

• the product of the maximum force times the maximum displacement.

If you push twice as hard against a stationary brick wall, the amount of work you do

• halved.

• remains constant but non-zero.

• doubled.

• remains constant at zero.