If M be the mass of the earth, R its radius (assumed spherical) and G, gravitational constant, then the amount of work that must be done on a body of mass m so that it completely escapes from the gravity of the earth is given by :

Options

A. The tension in the string in (b) is `10 N`.
B. The tension in the string in (b) is `7 N`.
C. The reading of the scale in (b) is `17 N`
D. The reading of the scale in (c) is `24 N`.

Answer

B, C, D

Explanation

Density of the block `=1/(3xx10^(-4)) kg//m^(3)=10/3xx10^(3)kg//m^(3)`
Buoyant force `B=3xx10-4xx103xxg=3N`
`:. TB=10=3=7N`
Reading of `B=14+3=17N`
Reading of `C=[14+(10-3)+3]N=24N`