Question

A particle of mass 200 g is moving in a circle of radius 2 m. The particle is just 'looping the loop'. The speed of the particle and the tension in the string at highest point of the circular path are (g = 10 $m{s}^{-2}$)

• A. 4 $m{s}^{-1}$, 5 N
• B. 4.47 $m{s}^{-1}$, zero
• C. 2.47 $m{s}^{-1}$, zero
• D. 1 $m{s}^{-1}$, zero

Answer 1

Answer: (B)

4.47 $m{s}^{-1}$, zero

The body will revolve in the circle if the string does rot
sag.

$T_H>0$

or, $T_H+mg=\frac{m{u}^2}{r}$

For minimum, $T_H=0$ $\therefore u=\sqrt{rg}=4.47m{s}^{-1}$