Most Important Selected Qs for JEE AdvancedPhysicsLaws of Motion
The linear mass density of a rod of length depends on the distance x from upper end as = ₀ e ^ 2 x . Rod is moved up by applying a force F. Find the correct statement.
Options
- AThe minimum force required to move the rod up is ₀ 2 (e^ 2 -1 ) g .
- BThe tension at the mid point of the rod is F / 2
- CThe acceleration of the rod is g upward if F= _ d (e^ 2 t -1 ) g
- DThe tension at the mid-point will be less if rod moves on a smooth horizontal surface.
Correct answer
D. The tension at the mid-point will be less if rod moves on a smooth horizontal surface.
Step-by-step solution
For ( A ): F_ =m g= ( d m ) g= ( d ) g= ₀^ ( ₀ e^ 2 x d x ) g= ₀ 2 (e^ 2 -1 ) g For (B) : Lower half is heavier so, T F 2 For (C) : F-m g=m a F=m(g+a)= ₀ (e^ 2 -1 ) g and a=g