JEE — Torque EquilibriumHardQuestion 30367
Question
A uniform ladder (mass M, length L) leans against a smooth wall, foot on rough floor. For equilibrium, the torque equation about the base gives the wall reaction N_w as:
- AMgL cosθ/(2 sinθ)
- BMg tanθ/2
- CMg/(2 tanθ)Correct
- DMg cosθ/2
Correct answer
Mg/(2 tanθ)
Explanation
Taking torques about the base: N_w × L sinθ = Mg × (L/2) cosθ. N_w = Mg cosθ/(2 sinθ) = Mg/(2 tanθ).