Question

A body of mass 10 kg is attached to a wire 0.3 m long. Its breaking stress is . The area of cross-section of the wire is . What is the maximum angular velocity with which it can be rotated in the horizontal circle

• A. 1 rad/sec
• B. 2 rad/sec
• C. 4 rad/sec
• D. 8 rad/sec

Answer 1

Answer: (C)

4 rad/sec

Answer 2

Breaking force = centrifugal force

Breaking stress × area of cross-section =$m \omega ^ { 2 } l$

$4.8 \times 10 ^ { 7 } \times 10 ^ { - 6 } = 10 \times \omega ^ { 2 } \times 0.3$ $\Rightarrow \omega = 4 \mathrm { rad } / \mathrm { sec }$