Static Friction

Q. $F_1$ is the force of friction on a box just before it starts sliding, and $F_2$ is the force of friction when it starts sliding. Which of the following is true about $F_1$ and $F_2$?

1. Directions of $F_1$ and $F_2$ are opposite.
2. The magnitude of $F_1$ is more than $F_2$ and they act in the same direction.
3. The magnitude of $F_2$ is more than $F_1$.
4. $F_1$ and $F_2$ are equal in magnitude

Q.

A block is kept at rest on ground. When a horizontal force is applied to the block, it doesn't move. The force which opposes this external force while the block is at rest is known as:

1. Magnetic force

2. Static friction

3. Sliding friction

4. None of these

Q. Wheels have the ability to use static friction which usually opposes motion and move forward.

1. True
2. False

Q.

Friction that exists between two surfaces in contact, when there is no relative motion between them is called as?

1. Rolling friction

2. Static friction

3. Limiting friction

4. Sliding friction

Q.

Of the various types of friction, which has the maximum value between two surfaces in contact?

1. Static

2. Sliding

3. Rolling

4. Walking

Q. Case I: A block of mass 1 kg is placed on a rough horizontal surface.
Case II: A block of mass 1 kg is placed on a rough horizontal surface and another identical block is kept over it.
Choose the correct statement.

1. Sliding friction is greater than static friction
2. No frictional force acts after the cart comes in motion.
3. Air friction is greater during first few steps of motion.
4. Static friction is greater than sliding friction.

Q. The frictional force which acts before relative motion starts between two surfaces in contact is known as:

1. Sliding friction
2. Static friction
3. Rolling friction
4. Dragging friction

Q.

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

1. sliding friction

2. rolling friction

3. kinetic friction

4. static friction

Q.

A block, kept on ground, requires 10 N of horizontal force to just start moving. If we apply a force of 5 N on the block in horizontal direction, what will be the magnitude of frictional force acting on it?

1. 0 N
2. 100 N

3. 5 N

4. 50 N

Q. A force of 10 N is applied to a block as shown below. If the block remains stationary, what is the magnitude of static friction acting on the block?

1. 10 N
2. 0 N
3. Less than 10 N
4. Greater than 10 N