NTA Abhyas JEE Main2020PhysicsRotational MotionPractice
A cubical block of side moving with a velocity v on a horizontal smooth plane as shown. It hits a ridge at point O and sticks to it (collision is perfectly inelastic). The angular speed of the block after it hits O is
Options
- A3 v 4 a
- B3 v 2 a
- C3 v 2 a
- DZero
Correct answer
A. 3 v 4 a
Step-by-step solution
Net torque about O is zero. Therefore, angular momentum L about point O will be conserved or, L i = L f Mv a 2 = I 0 ω = I com + Mr 2 ω = Ma 2 6 + M a 2 2 ω = 2 3 Ma 2 ω ∴    ω = 3 v / 4 a