Question

A small ball describes a horizontal circle on the smooth inner surface of a conical funnel. If the height of the plane of the circle above the vertex be 10 cm, what is the speed of the particle?

• A. 2m/s
• B. 4 m/s
• C. 16 m/s
• D. 1 m/s

Answer 1

The correct option is D 1 m/s


As it is clear from figure,
R sin $\theta =mg$
$Rcos\theta =\frac{m{v}^2}{r}tan\theta =\frac{rg}{v^2}$
On substituting we get $v=1m{s}^{-1}$