A ladder is leaned against a smooth wall and it is allowed to slip on a frictionless floor. Which figure represents the path followed by its center of mass?
| 1. | |
2. | |
| 3. | 4. |
A bob of mass m attached to an inextensible string of length l is suspended from vertical support. The bob rotates in a horizontal circle with an angular speed about the vertical. About the point of suspension.
| 1. | Angular momentum is conserved |
| 2. | Angular momentum changes in magnitude but not in the direction |
| 3. | Angular momentum changes in direction but not in magnitude |
| 4. | Angular momentum changes both in direction and magnitude |
A uniform cubical block of side L rests on a rough horizontal surface with coefficient of friction . A horizontal force F is applied on the block as shown. If there is sufficient friction between the block and the ground, then the torque due to normal reaction about its centre of mass is:
1.
2.
3.
4.
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. | \(2~\text{J}\) |