A stone of mass 1 kg is tied with a string and it is whirled in a vertical circle of radius 1 m. If tension at the highest point is 14 N, then velocity at lowest point will be

Question

A stone of mass 1 kg is tied with a string and it is whirled in a vertical circle of radius 1 m. If tension at the highest point is 14 N, then velocity at lowest point will be (A) 3 m / s (B) 4 m / s (C) 6 m / s (D) 8 m / s

Tardigrade Admin · Accepted Answer

T+m g=(m v2/R) (at the highest point) 14=(1(v2)/R(1))+10 v2=4 ⇒ v=2 m / s Using mechanical energy conservation. (1/2)(1) u2=(1/2)(1)(22)+1(10)(2) u2=64 ⇒ u=8 m / s

Q. A stone of mass $1 k g$ is tied with a string and it is whirled in a vertical circle of radius $1 m$ . If tension at the highest point is $14 N$ , then velocity at lowest point will be

3 m / s

4 m / s

6 m / s

8 m / s

$T + m g = \frac{m v ^{2}}{R}$ (at the highest point)
$14 = \frac{1 ( v ^{2} )}{R ( 1 )} + 10$
$v^{2} = 4 \Rightarrow v = 2 m / s$
Using mechanical energy conservation.
$\frac{1}{2} (1) u^{2} = \frac{1}{2} (1) (2^{2}) + 1 (10) (2)$
$u^{2} = 64$
$\Rightarrow u = 8 m / s$

Q. A stone of mass 1kg is tied with a string and it is whirled in a vertical circle of radius 1m. If tension at the highest point is 14N, then velocity at lowest point will be