Question

what is the work done by the force of gravity on a satellite moving around the earth justify your answer​

Answer 1

Answer:

1 unit of energy is equal to 1 kilowatt hour (kWh).

1 unit = 1 kWh

1 kWh = 3.6 x10^{6}10

6

J

Therefore, 250 units of energy = 250 x 3.6 × 10^{6}10

6

= 9 x 10^{8}10

8

J.

Answer 2

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Work is said to be done when a force applied to an object moves that object. We can calculate work by multiplying the force by the movement of the object.

The work done on the satellite by the Earth is zero.

Work is done whenever the given two conditions are satisfied:

• A force acts on the body.

• There is a displacement of the body by applying force in or opposite to the direction of the force.

When a person holds a bundle of hay over his head, there is no displacement in the hay bundle. Although the force of gravity is acting on the bundle, the person is not applying any force on it. Hence, in the absence of force, work done by the person on the bundle is zero. His head gets tired as he experiences muscular fatigue. This fatigue is due to the conversion of chemical energy into thermal energy by muscular effort. The person has done no work as his effort causes no displacement of the bundle over his head, i.e., S = 0.