A string is wrapped along the rim of a wheel of moment of inertia \(0.10\) kg-m2 and radius \(10\) cm. If the string is now pulled by a force of \(10\) N, then the wheel starts to rotate about its axis from rest. The angular velocity of the wheel after \(2\) s will be:
1. | \(40\) rad/s | 2. | \(80\) rad/s |
3. | \(10\) rad/s | 4. | \(20\) rad/s |
A disc of radius \(2~\text{m}\) and mass \(100~\text{kg}\) rolls on a horizontal floor. Its centre of mass has a speed of \(20~\text{cm/s}\). How much work is needed to stop it?
1. \(1~\text{J}\)
2. \(3~\text{J}\)
3. \(30~\text{J}\)
4. \(2~\text{J}\)