Question

What are the dimensions of universal gravitational constant?

(a) [M^2L^3T^2]

(b) [M^-1 L^3 T^-2]

(c) [M^-1 L^3 T^2]

(d) [M^1 L^3 T^-2]

I have been asked this question in an interview.

This intriguing question originated from The Gravitational Constant in section Gravitation of Physics – Class 11

Answer 1

Right option is (b) [M^-1 L^3 T^-2]

Explanation: N m^2/kg^2 are the units of universal gravitational constant.

N m^2/kg^2 = m^3/ (kgs^2)

 = m^3kg^-1s^-2

Hence, the dimensions are [M^-1 L^3 T^-2].