Q. A ball of mass 0.25 kg attached to the end of a string of length 1.96 m is moving in a horizontal circle. The string will break if the tension is more than 25N. What is the maximum speed with which the ball can be moved?
A) $14\ ms^{- 1}$
B) 3 $ms^{- 1}$
C) 3.92 $ms^{- 1}$
D) 5 $ms^{- 1}$
Explanation
(a) 25 = 0.25$\ \times v^{2}/1.96$
or $v = (25 \times 1.96/0.25)^{1/2} = 5 \times \frac{14}{5} = 14ms^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.