Advanced — Ladder ProblemHardQuestion 30380
Question
A uniform rod (mass M, length L) leans against frictionless wall, smooth floor. It will:
- AStay in any position
- BSlide only if θ < angle of repose
- CAlways slide (cannot be in equilibrium with both surfaces frictionless)Correct
- DRotate about its centre
Correct answer
Always slide (cannot be in equilibrium with both surfaces frictionless)
Explanation
With both surfaces frictionless, the only horizontal forces are the wall's normal force and the floor's normal force. Wall pushes horizontally, floor pushes vertically → net torque cannot balance for any angle → cannot be in equilibrium.