Question

What should be the velocity of rotation of earth due to rotation about its own axis so that the weight of a person becomes (3)/(5) of the present weight at the equator. Equatorial radius of earth is 6400km.

• A. \(8.7 \times 10^{-4}\,\text{rad/s}\)
• B. \(7.8 \times 10^{-4}\,\text{rad/s}\)
• C. \(6.7 \times 10^{-4}\,\text{rad/s}\)
• D. 7.4 × 10⁻3rad/s

Hint:

At the equator, effective gravity is reduced due to centrifugal force: gₑff = g - ω² R Always use this relation when Earth’s rotation affects weight.

Answer 1

The Correct Option is B