Question

Choose the correct statement(s).

The average acceleration due to gravity 'g' on the surface of the earth decreases if :

• A. we go down from the surface of the earth towards its centre
• B. we go up from the surface of earth
• C. we go from the equator towards the poles on the surface of the earth
• D. the rotational velocity of the earth is increased

Answer 1

Answer: (A), (B), (D)

The correct options are
A we go down from the surface of the earth towards its centre
B we go up from the surface of earth
D the rotational velocity of the earth is increased

The gravitational acceleration at height $h$ from earth's surface is $g_h=g[1-\frac{2h}{R}]$ and at depth $d$ from earth's surface is $g_d=g[1-\frac{d}{R}]$

Thus, in both cases , the acceleration will decrease for increasing height and depth.

The acceleration due to gravity is maximum at poles and minimum at the equator because the centrifugal force is vanishes at poles and maximum at the equator. The value of gravitational acceleration will increase from the equator towards the poles.

If the rotational velocity is increased, the centrifugal force will increase and so that the acceleration will decrease.