A metre stick is pivoted about its centre. A piece of wax of mass 20 g travelling horizontally and perpendicular to it at 5 m / s strikes and adheres to one end of the stick so that the stick starts to rotate in a horizontal circle. Given the moment of inertia of the stick and wax about the pivot is 0.02 kg m 2, the initial angular velocity of the stick is

Question

A metre stick is pivoted about its centre. A piece of wax of mass 20 g travelling horizontally and perpendicular to it at 5 m / s strikes and adheres to one end of the stick so that the stick starts to rotate in a horizontal circle. Given the moment of inertia of the stick and wax about the pivot is 0.02 kg m 2, the initial angular velocity of the stick is (A) 1.58 rad / s (B) 2.24 rad / s (C) 2.50 rad / s (D) 5.00 rad / s

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/b63c2adc5dade25d80891dad515b805e-.png" /> L=l ω (20/1000) × 5 × (l/2)=0.02 ω ω=2.5 rad / s

1.58 rad / s

2.24 rad / s

2.50 rad / s

5.00 rad / s

L=lω 100020​×5×2l​=0.02ω ω=2.5rad/s

$L = l ω$
$\frac{20}{1000} \times 5 \times \frac{l}{2} = 0.02 ω$
$ω = 2.5 r a d / s$