Work and Energy

Work done upon a body is :

• A vector quantity

• A scalar quantity

• Both A and B are correct

• None of these

In tug of war work done by loosing team is :

• Zero

• Positive

• Negative

• None of these

A particle of mass m is at rest is acted upon by a force F for a time t. Its kinetic energy after an interval of t is :

• F²t²/m

• F²t²/2m

• F²t²/3m

• Ft/2m

One atomic mass unit (a.m.u) is equal to :

• 1 eV of energy

• 931 eV of energy

• 1 MeV of energy

• 931 MeV of energy

A device which converts the electrical energy into mechanical energy is called :

• Dynamo

• Electromagnet

• Electric motor

• Generator

In a simple pendulum mass of bob is 100 g and effective length is L. Work done on the pendulum in one complete oscillation by gravitational force is:

• 1/4 x mgL

• 1/2 x mgL

• Zero

• mgL

Energy possessed by a body by virtue of its motion is called :

• Potential energy

• Kinetic energy

• Gravitational energy

• None

A boy pushes a book kept on a table by applying a force of 4.5 N. find the work done by the force, if book is displaced through 30 cm along the direction of push

• 1.10 J

• 1.25 J

• 1.35 J

• None

The kinetic energy of an object is K. If its velocity is doubled then its kinetic energy will be :

• K

• 2K

• K/2

• 4K

Ratio of potential energy of body A and body B will be :

• 2/3

• 3/2

• 1/3

• 3/4