A small object of uniform density rolls up a curved surface with an initial velocity $v^{\prime}$. It…
- ring
- solid sphere
- hollow sphere
- disc
Solution
Given $h=\frac{3 v^2}{4 g}$
$v^2=\frac{2 g h}{1+\frac{k^2}{r^2}}=\frac{2 g 3 v^2}{4 g\left(1+\frac{k^2}{r^2}\right)}=\frac{6 g v^2}{4 g\left(1+\frac{u^2}{v^2}\right)}$
$1=\frac{3}{2\left(1+\frac{k^2}{v^2}\right)}$
or $1+\frac{k^2}{r^2}=\frac{3}{2}$ or $\frac{k^2}{r^2}=\frac{3}{2}-1=\frac{1}{2}$
$k^2=\frac{1}{2} r^2$ (Equation of disc)
Hence, the object is disc.
Asked in: NEET 2013 (All India)