Page 83 - Force 10

18. When dropped from the same height a body reaches the ground quicker at poles than

at the equator, why? OR, Object falls faster in the polar region even if identical objects are

dropped from the same height, why?

The acceleration due to gravity is more at poles than at the equator

because acceleration due to gravity is inversely proportional to radius ( i.e..

1
g∝ ), being the earth oval in shape radius of pole is lesser than equator (
2
i.e.. > ). When the initial velocities and distance travelled are same, the

time taken by body is less if the acceleration due to gravity is more. Hence,

when dropped from the same height a body reaches the ground quicker at

poles than at equator.

19. A man jump six times as high on the on the moon as that of the earth. Justify.

The value of acceleration due to gravity ‘g’ on the surface of the earth is six times greater

than the moon i.e.. ℎ = 6 . As a result, the gravitational pull is 6 times less on the

moon than the earth. For the same gain of potential energy in both cases we have;

ℎ =

m ℎ = m ℎ [ = ℎ ]

m 6 ℎ = m ℎ [ = 6 ]

6ℎ = ℎ