Page 77 - Force 10

Q.5. The acceleration due to gravity of the earth is more at poles than

at equator.

Since acceleration due to gravity is inversely proportional to square

of radius of heavenly body where radius is more at equator than its

poles. Greater acceleration due to gravity at the poles causes the

falling object to travel more distance at the same interval of time than

at equator. Since acceleration due to gravity is directly proportional to

velocity where velocity is directly proportional to distance travelled

keeping time constant.

Q.6. Tides develop in sea and ocean shores but not in Phewa lake,

why?

Sea and Ocean cover more area, but lake covers very less area.

The transverse waves of water called tide can get sufficient area or

distance to increase its amplitude by decreasing the wavelength. As

a result, high tides develop whereas water in lake don’t get sufficient

distance to travel to raise sufficient height of tide in lake.