Question

A ball of mass $0.25 \,kg$ attached to the ends of a string of length $1.96 \,m$ is rotating in a horizontal circle. The string will break, if tension is more than $25\, N$. What is the maximum velocity with which the ball can be rotated?

• A. 3 m/s
• B. 5 m/s
• C. 9 m/s
• D. 14 m/s

Answer 1

Answer: (D)

14 m/s

Answer 2

Given : $m=0.25 \,kg , l=1.96 \,m$ and $t=25\, N$ Centrifugal force (tension) in the string is given by $F=\frac{m v^{2}}{r}$ $\Rightarrow v^{2} =\frac{F r}{m}$ $\Rightarrow v^{2} =\frac{25 \times 1.96}{0.25}=196$ $\Rightarrow v =\sqrt{196}$ $=14 \,m / s$