question_answer

If the earth has no rotational motion, the weight of a person on the equation is W. Detrmine the speed with which the earth would have to rotate about its axis so that the person at the equator will weight\[\frac{3}{4}W.\]Radius of the earth is 6400 km and \[g=10m/{{s}^{2}}.\]                                                                           [JEE Online 08-04-2017]

A) \[0.63\times {{10}^{-3}}rad/s\]

B)      \[0.28\times {{10}^{-3}}rad/s\]

C) \[1.1\times {{10}^{-3}}rad/s\]

D)      \[0.83\times {{10}^{-3}}rad/s\]

Correct Answer: A

Solution :

[a]