Question

when a sphere is allowed to move on rough inclined plane what is the direction frictional force ?​

Answer 1

Answer:

It will be the opposite direction of the motion of the sphere.

Explanation:

Hope it helps.

Answer 2

Answer:

Initially pure sliding is taking place, which means that velocity of the centre, v= v

0

(initial velocity) and angular velocity ω = 0.

Finally, pure rolling takes place which means that v=Rω

Friction always acts in the direction that opposes relative motion between the two surfaces. Therefore, friction will initially act in the direction opposite to motion of the sphere. This frictional force will cause a linear retardation => Option B is correct.

Since frictional force acts at a distance R from the centre, it produces a torque. This torque will cause angular acceleration. => Option C is correct.

An object is said to be rolling if the velocity of the point in contact with the ground is 0. This means that there is no relative velocity between the rough surface and sphere, therefore no friction will act once the sphere achieves pure rolling => Option D is correct.

Due to frictional force, v will decrease and ω will increase until v=Rω

At this point, pure rolling will be achieved and frictional force will stop acting. => Option A in incorrect