Question

A one kg stone attached to the end of a 60cm chain
is reolving at the rate of 3 revolutions/second. If
after 30s, it is making only one revolution per sec-
ond, find the mean torque
(a) 0.45N (b) 0.35Nm (c) 0.25Nm (d) 0.15Nm​

Answer 1

Given info : A one kg stone attached to the end of a 60cm chain is reolving at the rate of 3 revolutions/second.

To find : If after 30s, it is making only one revolution per second, find the mean torque.

Solution : torque = moment of inertia × angular acceleration

Moment of inertia , I = mr²

= 1kg × (0.6m)²

= 0.36 kgm²

angular acceleration, α = (ω - ω₀)/t

= (3 × 2π - 1 × 2π)/30 sec

= 4π/30 rad/s²

Now, torque = 0.36 × 4π/30 = 0.15 Nm

Therefore the mean torque would be 0.15 Nm

Answer 2

Answer:

Explanation:

Answer is attached