Work and Energy

This is an MCQ-based quiz on Work and Energy.

This includes Mechanical energy, Thermal energy, Potential energy, and Kinetic Energy.

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A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²)

6 × 10³ J 6 J 0.6 J zero

Two army persons A and B each of weight of 500 N climb up a rope through a height of 10 m. A takes 20 s while B takes 40 s to achieve this task. What is ratio of the powers of person A and B?

1 : 2 1 : 4 2 : 1 14 : 1

An iron sphere of mass 10 kg has the same diameter as an aluminum sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same.

Acceleration

Momenta

Potential energy

Kinetic energy

The work done on an object does not depend upon the

Displacement

Force applied

Angle between force and displacement

Initial velocity of the object

A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car

Does not change

Becomes twice to that of initial

Becomes 4 times that of initial

Becomes 16 times that of initial

When a body like earth is moving in a circular path the work done in that case is zero because:

Centripetal force acts in the direction of motion of the body Centripetal force acts along the radius of circular path Gravitational force acts along the radius of circular path Centrifugal force acts perpendicular to the radius of circular path

A car is accelerated on a leveled road and attains a velocity 4 times of its initial velocity. In this process, the kinetic energy of the car

Becomes twice to that of the initial Becomes four times to that of the initial Remains the same Becomes 16 times to that of the initial

The momentum of a bullet of mass 20 g fired from a gun is 10 kg m/s. The kinetic energy of this bullet in kJ will be:

25 2.5 0.25 5

A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is(g = 10 m/s2):

50 J 500 J 5 J 5000 J

One joule work is said to be done when

A force of 1 N displaces a body by 1 cm A force of 1 N displaces a body by 1 m A force of 1 dyne displaces a body by 1 m A force of 1 dyne displaces a body by 1 cm.

Potential energy of a body depends on its

Position Configuration Position and Configuration Mass and Velocity

When a coil spring is compressed, the work is done on the spring. The elastic potential energy

Increases Decreases Disappears Remains unchanged

If speed of a car becomes 2 times, its kinetic energy becomes

4 times 8 times 16 times 12 times

Commercial unit of energy is

Joule

KWH

Watt

Newton

Which one of the following is not the unit of energy?