Q. A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity $\omega_{0}.$ If the length of the string and angular velocity both are doubled, the tension in the string which was initially $T_{0}$ is now
A) $T_{0}$
B) $T_{0}/2$
C) $4T_{0}$
D) $8T_{0}$
Explanation
(d) Tension in the string $T_{0} = mR\omega_{0}^{2}$
In the second case $T = m(2R)\left( 4\omega_{0}^{2} \right) = 8mR\omega_{0}^{2} = 8T_{0}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.