Physics · 2015
JEE Main · 11 April 2015, Shift 1 · Q3
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…
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 $\displaystyle \mathrm{L}(\mathrm{L} \gg \mathrm{r})$ 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 $\displaystyle v$, the average force experienced by each support after a long time is (assume all collisions are elastic) :
Official answer
(2)
$\displaystyle \frac{\mathrm{m} v^2}{\mathrm{~L}-2 \mathrm{nr}}$
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JEE Main 2015 Physics question, with the answer from NTA’s final answer key. Where our answers come from.