The correct answer is (B) : 36 hours
\(T_{2}^2 = ( \frac{R_2}{R_1} )^3 T^2{_1}\)
\(⇒ T_2 = (3)^{3/2} × 7 ≈ 5.2 × 7\)
T2 ≅ 36 hrs

A body of mass $m$ is taken from the surface of earth to a height equal to twice the radius of earth ($R_e$). The increase in potential energy will be ____ ($g$ is acceleration due to gravity at the surface of earth)
If a body of mass 1 kg falls on the earth from infinity, it attains velocity \( v \) and kinetic energy \( k \) on reaching the surface of the earth. The values of \( v \) and \( k \) respectively are _______.
In mechanics, the universal force of attraction acting between all matter is known as Gravity, also called gravitation, . It is the weakest known force in nature.
According to Newton’s law of gravitation, “Every particle in the universe attracts every other particle with a force whose magnitude is,
On combining equations (1) and (2) we get,
F ∝ M1M2/r2
F = G × [M1M2]/r2 . . . . (7)
Or, f(r) = GM1M2/r2
The dimension formula of G is [M-1L3T-2].