Kinetic Friction

Q. A rectangular block is placed on a rough horizontal surface in two different ways as shown. If the same magnitude of force(F) is applied on the block in two cases, the frictional force acting between the block and the surface__________.

1. will depend on the area of contact of the block with the surface
2. will be more in case (ii)
3. will be more in case (i)
4. will be equal in both the cases

Q.

Explain why sliding friction is less than static friction.

Q. Which of the following produces least friction?

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

Q. Choose the factor which does not affect the frictional force on an object.

1. Roughness
2. Contact area
3. Material
4. Weight

Q. How does ball bearing reduce friction?

Q.

If the sliding friction between two surfaces is found to be 8N, then the static friction between these two surfaces is most likely to be:
(a) 5N
(b) 10N
(c) 4 N
(d) 2N

Q.

The friction which comes into play once an object starts moving on a table is called as?

1. Static friction

2. Sliding/dynamic friction

3. Limiting friction

4. Rolling friction

Q. A block of mass 5 kg is placed on a plank of mass 10kg which is placed on the smooth horizontal surface. If a 100 N force is applied on the plank, then acceleration of plank w.r.t ground is(coefficient of friction between block and plank μ(s)=μ(k)=0.4 and g=10m/s^2)-

Q. Sliding friction is than the static friction.

1. much greater
2. slightly more
3. less

Q. if the unit of mass is 1 kg unit of time is i minute and unit of acceleration is 10 m/s2 then unit of energy is

Q. A toy car is at rest, and a force of 70 N is applied to it in rightwards direction. If the frictional force between the toy and the floor is 20 N, determine the net force acting on the toy car.

Q. Between two given surfaces, the ratio of kinetic friction to the maximum value of static friction is:

1. equal to zero
2. less than one
3. greater than one
4. equal to one

Q. What kind of friction comes into play:
(a) when a block of wood kept on table moves slowly?
(b) when a block of wood kept on table just tends to move (or slip)?
(c) when a block of wood kept on cylindrical iron rods moves?

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. 50 N

3. 5 N

4. 100 N

Q. In a laboratory experiment on friction, a block of weight $135N$ lying on a rough horizontal table is pulled by a horizontal wire. The pull $\left(P\right)$ gradually increases until the block begins to move and continues to increase thereafter. Given figure shows a graph of the friction force $\left(f\right)$ on this block as a function of the pull $\left(P\right)$


The region of the graph where kinetic friction occur is

1. $P<50N$
2. $P>75N$
3. $P=0N$
4. $P<75N$

Q. The friction that acts when there is slipping between two surfaces in contact is known as:

1. static friction
2. kinetic friction
3. rolling friction
4. drag

Q.

What causes friction?

1. Irregularities on the two surfaces in contact

2. Color of the surfaces

3. Gravitational attraction between the surfaces

4. smoothness on the two surfaces in contact

5. Atmosphere around the surfaces

Q.

Why is sliding friction less than static friction

Q. A block, placed on a horizontal table, just starts moving when the applied horizontal force is 5 N. What can we say about the magnitude of friction acting on the block once it starts moving?

1. 5 N
2. 0 N
3. Less than 5 N
4. Greater than 5 N

Q.

what is the difference between limiting friction and static friction ?

Q. Find the value of force X, if the net force on the block is 4 N towards the left. Assume the frictional force between the block and the ground is 3 N.​

1. 17 N
2. 2 N
3. 5 N
4. 16 N

Q.

Which of the following is not a type of friction?

1. static friction

2. rolling friction

3. sliding friction

4. slow friction

Q.

It is easier to move a book on rollers than to drag it without rollers as the surface area in contact is reduced .

1. False

2. True

Q. A block is sliding on a horizontal surface at a speed of $1m{s}^{-1}$. The friction offered by the surface on the block is 1 N. A horizontal force is applied to the block to increase its speed to $2m{s}^{-1}$. Now, the friction offered by the table will be:

1. 1 N
2. 2 N
3. 3 N
4. 4 N

Q.

A ball is rolled along a table. What all forces are acting on the ball, after it leaves the table but before it hits the floor?

Q. A block is sliding down on an inclined plane. Identify the frictional force acting on the block.

1. 
2. 
3. 
4. 

Q. Select the examples in which sliding friction is acting on the body.

1. 
2. 
   
3. 
4. Parked Car
   

Q. A ball is rolled along a table. what all forces are acting up on it after it leave the table but before it hits the floor??

Q. If a child sitting on a slide does not slide down, it could be because of?

Q.

Force that opposes motion between two bodies sliding over each other?