# A large number $(n)$ of identical beads, each of mass $m$ and radius $r$ are strung on a thin smooth rigid horizontal rod of length $L(L>>r)$ and are at rest at random positions. The rod is mounted between two rigid supports (see figure). If one of the beads is now given a speed v, the average force experienced by each support after a long time is (assume all collisions are elastic):

Question:

A large number $(n)$ of identical beads, each of mass $m$ and radius $r$ are strung on a thin smooth rigid horizontal rod of length $L(L>>r)$ and are at rest at random positions. The rod is mounted between two rigid supports (see figure). If one of the beads is now given a speed v, the average force experienced by each support after a long time is (assume all collisions are elastic):

1. $\frac{\mathrm{mv}^{2}}{2(\mathrm{~L}-\mathrm{nr})}$

2. $\frac{m v^{2}}{L-2 n r}$

3. $\frac{\mathrm{mv}^{2}}{\mathrm{~L}-\mathrm{nr}}$

4. zero

JEE Main Previous Year Single Correct Question of JEE Main from Physics Laws of Motion chapter.

JEE Main Previous Year April 11, 2015

Correct Option: 2

Solution:

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