A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s^-2, the work done by her after climbing 2 m will be:

A. 200 J B. 800 J

C. 8000 J D. 2000 J

An object of mass 5 kg falls from a height of 5 m above the ground. The loss of potential energy of the mass is :

Water stored in a dam possesses:

A. No energy

B. Electrical energy

C. Kinetic energy

D. Potential energy

A car is accelerated on a leveled road and acquires a velocity 4 times of its initial velocity. During this process, the potential energy of the car:

A. Does not change

B. Becomes twice that of initial potential energy

C. Becomes 4 times that of initial potential energy

D. Becomes 16 times that of initial potential energy.

Fill in the following blanks with suitable words:

(a) Work is measured as a product of ……… and ……………..

(b) The work done on a body moving in a circular path is ………………

(c) 1 joule is the work done when a force of one ……………..moves an object through a distance of one …………… in the direction of ……………….

(d) The ability of a body to do work is called ………. . The ability of a body to do work because of its motion is called ………..

(e) The sum of the potential and kinetic energies of a body is called ………… energy.

Write true or false for the following statements :

When an arrow is released from a bow, potential energy changes into kinetic energy.

Find the energy possessed by an object of mass 10 kg when it is at a height of 6m above the ground. [g = 9.8 ms^-1]

An object of mass 1 kg has a potential energy of 1 joule relative to the ground when it is at a height of :

To what height should a body of mass 5 kg be raised so that its potential energy is 490 J? [g = 9.8 m/s²]

When a stone of mass ‘m’ falls through a vertical height ‘d’, the decrease in the gravitational energy is :