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The upper half of an inclined plane with inclination $ϕ$ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is

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Important Questions on Friction

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches

30 °

, the box starts to slip and slides

4.0 m

down the plank in

4.0 s

. The coefficients of static and kinetic friction between the box and the plank will be, respectively:
Question Image

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

When a body is placed on a rough plane (coefficient of friction

= μ

) inclined at an angle

θ

to the horizontal, its acceleration is (acceleration due to gravity

= g

)

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

Consider a block kept on an inclined plane (inclined at $45 °$ ) as shown in the figure. If the force required to just push it up the incline is $2$ times the force required to just prevent it from sliding down, the coefficient of friction between the block and inclined plane $(µ)$ is equal to :

Question Image .

EASY

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

Given in the figure are two blocks

A

and

B

of weight

20 N

and

100 N

, respectively. These are being pressed against a wall by a force

F

and kept in equilibrium as shown. If the coefficient of friction between the blocks is

0.1

and between block

B

and the wall is

0.15

, the frictional force applied by the wall on block

B

is:

HARD

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A box when dropped from a certain height reaches the ground with a speed

v

. When it slides from rest from the same height down a rough inclined plane inclined at an angle

45^{o}

to the horizontal, it reaches the ground with a speed

\frac{v}{3}

. The coefficient of sliding friction between the box and the plane is (acceleration due to gravity is

10 m s^{- 2}

)

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block of mass

m

slides down the plane inclined at angle

30 °

with an acceleration

\frac{g}{4}

. The value of coefficient of kinetic friction will be :

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block of mass

10 kg

is kept on a rough inclined plane as shown in the figure. A force of

3 N

is applied on the block. The coefficient of static friction between the plane and the block is

0.6 .

What should be the minimum value of force

P,

such that the block does not move downward? (take

g = 10 m s^{- 2}

)

EASY

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block A of mass 4 kg is placed on another block B of mass 5 kg, and the block B rests on a smooth horizontal table. If the minimum force that can be applied on A so that both the blocks move together is 12 N, the maximum force that can be applied on B for the blocks to move together will be :

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A body of mass

m

is launched up on a rough inclined plane making an angle of

30 °

with the horizontal. The coefficient of friction between the body and plane is

\frac{\sqrt{x}}{5}

, if the time of ascent is half of the time of descent. The value of

x

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

The normal reaction

N

for a vehicle of

800 kg

mass, negotiating a turn on a

30 °

banked road at maximum possible speed without skidding is ____

\times 10^{3} kg m s^{- 2}

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A car is negotiating a curved road of radius

R

. The road is banked at an angle

θ

. The coefficient of friction between the tyres of the car and the road is

μ_{s}

. The maximum safe velocity on this road is:

EASY

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block is released from rest on a

45 °

smooth incline and slide a distance

d

. The time taken to slide the same distance is

n

times as much to slide on a

45 °

rough incline than on the smooth incline. The coefficients of friction for the rough incline is

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block

A

of mass

m_{1}

rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of table and from its other end another block

B

of mass

m_{2}

is suspended. The coefficient of kinetic friction between the block and the table is

μ_{k}

. When the block

B

is sliding on the table, the tension in string is:

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

The time taken by an object to slide down

45 °

rough inclined plane is

n

times as it takes to slide down a perfectly smooth

45 °

incline plane. The coefficient of kinetic friction between the object and the incline plane is:

HARD

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A small box resting on one edge of the table is struck in such a way that it slides off the other edge,

1 m

away, after

2

seconds. The coefficient of kinetic friction between the box and the table

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A heavy box is to be dragged along a rough horizontal floor. To do so, the person

A

pushes it at an angle

30 °

from the horizontal and requires a minimum force

F_{A}

, while the person

B

pulls the box at an angle

60 °

from the horizontal and needs minimum force

F_{B}

. If the coefficient of friction between the box and the floor is

\frac{\sqrt{3}}{5}

, the ratio

\frac{F_{A}}{F_{B}}

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block of mass

m

is placed on a surface with a vertical cross section given by

y = \frac{x^{3}}{6}

. If the coefficient of friction is

0.5

, the maximum height above the ground at which the block can be placed without slipping is

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

If a block of mass '

m

' placed on a plane inclined at an angle

θ

, is on the verge of sliding, then the coefficient of friction between the block and the plane is given by

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A brick of mass $2 kg$ slides down an incline of height $5 m$ and angle $30 ° .$ If the coefficient of friction of the incline is $\frac{1}{2 \sqrt{3}},$ the velocity of the block at the bottom of the incline is (Assume the acceleration due to gravity is $10 m / s^{2})$

MEDIUM

Physics>Mechanics>Friction>Motion on Rough Inclined Plane

A block of mass $5 kg$ is kept against an accelerating wedge with a wedge angle of $45 °$ to the horizontal. The co-efficient of friction between the block and the wedge is $μ = 0.4$ . What is the minimum absolute value of the acceleration of the wedge to keep the block steady. Assume $g = 10 m s^{- 2}$

Question Image

The upper half of an inclined plane with inclination ϕ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is

Important Questions on Friction

Learn and Prepare for any exam you want !

The upper half of an inclined plane with inclination $ϕ$ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is