Question

A 0.17-kg ball on a stick is whirled on a vertical circle at a constant speed. When the ball is at the three o'clock position, the stick's tension is 15 N.
(a) Find the tension in the stick when the ball is at the twelve o'clock position.
(b)Find the tension in the stick when the ball is at the six o'clock position.

Answer 1

here,

mass of ball , m = 0.17 kg

force of gravity , Fg = m * g = 0.17 * 9.81 = 1.67 N

let the speed of ball be v at 3 oclock position

the tension at that position , T = sqrt(Fc + Fg)

15 = sqrt(Fc + 0.17 * 9.81)

Fc = 14.94 N

a)

the tension in the stick when the ball is at the twelve o'clock position, Tt = Fc - Fg

Tt = 14.94 - 1.67 N = 13.27 N

c)

the tension in the stick when the ball is at the six o'clock position , Tb = Fg + Fc

Tb = 14.94 N + 1.67 N = 16.61 N