JEE Main20206 Sep 2020Morning ShiftPhysicsLaws of MotionActual
An insect is at the bottom of a hemispherical ditch of radius 1 m . It crawls up the ditch but starts slipping after it is at height h from the bottom. If the coefficient of friction between the ground and the insect is 0 . 75 , then h is : g = 10 m s - 2
Options
- A0 . 20   m
- B0 . 45   m
- C0 . 60   m
- D0 . 80   m
Correct answer
A. 0 . 20   m
Step-by-step solution
mgsin θ = μ mgcos θ tan θ = μ = 0 . 75 ⇒ θ = 37 cos θ = R - h R cos 37 = 1 - h 1 ⇒ h = 0 . 2