A ball of mass 0.6kg attached to a light inextensible string rotates in a vertical circle of radius 0.75m such that…

Q: A ball of mass 0.6 kg attached to a light inextensible string rotates in a vertical circle of radius 0.75 m such that it has speed of 5 ms-1 when the string is horizontal. Tension in the string when it is horizontal on other side is (g =10 ms-2)

(a) 30 N

(b) 26 N

(c) 20 N

(d) 6 N

Ans: (c)

Sol: $ \displaystyle T = \frac{m v^2}{r} $

$ \displaystyle T = \frac{0.6 \times (5)^2}{0.75} $