Relative Motion

Q.

A batsman hits a cricket ball which then rolls on level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because

1. the batsman did not hit the ball hard enough.

2. velocity is proportional to the force exerted on the ball.

3. there is a force on the ball opposing the motion.

4. there is no unbalanced force on the ball, so the ball would want to come to rest.

Q.

Is static friction greater than rolling friction?

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Q.

Friction that exists between two surfaces in contact when there is no relative motion between them is known as ______.

1. kinetic friction

2. rolling friction

3. sliding friction

4. static friction

Q.

Whenever a body is in motion, there is always_________ to oppose the motion.

Q.

The force produced when an object slides over a surface____________.

Q. A block is sliding down a fixed inclined plane. The direction of frictional force acting on the block is down the inclined plane.

1. True
2. False

Q.

There are two surfaces, A and B that are in contact with each other. Consider the following situations:
Situation I: Both A and B are at rest.
Situation II: A is moving over B, while B is at rest.
Situation III: B is moving over A, while A is at rest.

In which of the given situations would you expect the sliding frictional force to come into play?

1. Situation I only

2. Situation II

3. Both Situation I and Situation II

4. Situation III

Q.

Define Friction

Q.

A car is at rest at a distance of $2m$ from a tree. If the position of the car does not change with time, the car can be said to be in motion with respect to the tree.

1. True

2. False

Q.

Try to move your fathers scooter. Does it require force to move? Once it has started moving, do you find it easy to push it further. If yes, why?

Q.

Question 8
Answer the following questions:
A. Why is sliding friction less than static friction between the same surfaces?
B. A book of mass 1 kg is kept at rest on a table. The maximum value of static friction is 200 N and sliding friction is 180 N.
i. If we apply a force of 190 N, will the body move?
ii. If we apply a force of 210 N, will the body move?

Q. The direction of frctional force is ___.

1. in the direction of motion of the body
2. opposite to the direction of motion of the body
3. opposite to the applied force on the body
4. along the applied force on the body.

Q.

Friction opposes ___motion between two surfaces.

Q.

When a book placed on a horizontal desk is pushed towards right, in which direction does the force of friction act on the book?

1. It will act towards right.

2. It will act towards left.

3. It will act vertically downwards.

4. It will act vertically upwards.