Question

A particle describes a horizontal circle on the smooth inner surface of conical funnel whose vertex angle is ${90}^0$. If the height of the plane of the circle above the vertex is $9.8cm$, the speed of the particle is:

• A. $\sqrt{9.8}$ m/sec
• B. $0.98m/s$
• C. $19.6m/s$
• D. $14.7m/s$

Answer 1

The correct option is B $0.98m/s$

$\frac{N}{\sqrt{2}}=mg\Rightarrow N=\sqrt{2}mg-\left(1\right)$
and $\frac{N}{\sqrt{2}}=\frac{m{V}^2}{r}$
$mg=\frac{m{V}^2}{r}$
$V=\sqrt{rg}$
$=\sqrt{\frac{\left(9.8\right)\times 9.8}{100}}$
$V=0.98m/s$