Page 75 - Force 10

Give Reasons:

Q.1. Weight of an object decreases inside the mine, why?

When an object is taken inside a mine the effective mass of the

earth to cause weight decreases. Decrease in mass causes the weight

to decrease since weight is directly proportional to mass of heavenly

body keeping mass of an object and radius of heavenly body

constant. (W∝ )

Q.2. An object weight more at the pole of the earth than at the

equator, why?

The earth is not perfectly sphere, it is flattened from the pole and

buldge out at equator. As a result, it has greater radius at the equator

and lesser at the poles. Decrease in radius causes the weight to

increase at poles and vice versa at equator. Since weight is inversely

1
proportional to the square of radius of heavenly body (i.e.. W∝ )
2
keeping mass of heavenly body and mass of an object constant.