Static and Kinetic Friction

Interactive Feed

JEE Main 2021

An inclined plane making an angle of $3 0^{\circ}$ with the horizontal is placed in a uniform horizontal electric field $200 N/C$ as shown in the figure. A body of mass $1 kg$ and charge $5 mC$ is allowed to slide down from rest at a height of $1 m$ . If the coefficient of friction is $0.2$ , find the time taken by the body to reach the bottom. [Take, $g = 9.8 m/s^{2}$ , $sin 3 0^{\circ} = \frac{1}{2}, cos 3 0^{\circ} = \frac{3}{2}$ ]

0.92 s

(B)

0.46 s

(C)

2.3 s

(D)

1.3 s

JEE Main 2021, 17 March Shift-II

LEVELJEE Advanced

A body of mass $1 kg$ rests on a horizontal floor with which it has a coefficient of static friction $1/ 3$ . It is desired to make the body move by applying the minimum possible force $F$ newton. The value of $F$ will be ............... . (Round off to the nearest integer) (Take, $g = 10 ms^{- 2}$ )

JEE Main 2021, 17 March Shift-I

LEVELJEE Main

Two blocks ( $m = 0.5$ kg and $M = 4.5$ kg) are arranged on a horizontal frictionless table as shown in figure. The coefficient of static friction between the two blocks is $3/7$ . Then, the maximum horizontal force that can be applied on the larger block so that the blocks move together is ...... N. (Round off to the nearest integer. Take, $g = 9.8 ms^{- 2}$ )

JEE Main 2021, 24 Feb Shift-I

LEVELJEE Advanced

An inclined plane is bent in such a way that the vertical cross-section is given by $y = \frac{x ^{2}}{4}$ where, $y$ is in vertical and $x$ in horizontal direction. If the upper surface of this curved plane is rough with coefficient of friction $μ = 0.5$ , the maximum height in cm at which a stationary block will not slip downward is .......... cm.

JEE Main 2020, 6 Sep Shift-I

LEVELJEE Main

An insect is at the bottom of a hemispherical ditch of radius $1 m$ . It crawls up the ditch but starts slipping after it is at height $h$ from the bottom. If the coefficient of friction between the ground and the insect is $0.75$ , then $h$ is (Take, $g = 10 ms^{- 2}$ )

(A)

0.20 m

(B)

0.45 m

(C)

0.60 m

(D)

0.80 m

JEE Main 2014

LEVELJEE Advanced

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

(A)

\frac{1}{6} m

(B)

\frac{2}{3} m

(C)

\frac{1}{3} m

(D)

\frac{1}{2} m

JEE Main 2019, 10 April Shift-II

LEVELJEE Advanced

Two blocks $A$ and $B$ of masses $m_{A} = 1 kg$ and $m_{B} = 3 kg$ are kept on the table as shown in figure. The coefficient of friction between $A$ and $B$ is $0.2$ and between $B$ and the surface of the table is also $0.2$ . The maximum force $F$ that can be applied on $B$ horizontally, so that the block $A$ does not slide over the block $B$ is [Take, $g = 10 m/s^{2}$ ]

A block rests on a rough inclined plane making an angle of $3 0^{\circ}$ with the horizontal. The coefficient of static friction between the block and the plane is $0.8$ . If the frictional force on the block is $10 N$ , the mass of the block (in $kg$ ) is ( $g = 10 m/s^{2}$ )

A smooth block is released at rest on a $4 5^{\circ}$ incline and then slides a distance $d$ . The time taken to slide is $n$ times as much to slide on rough incline than on a smooth incline. The coefficient of friction is

(A)

μ_{k} = 1 - \frac{1}{n ^{2}}

(B)

μ_{k} = 1 - \frac{1}{n ^{2}}

(C)

μ_{s} = 1 - \frac{1}{n ^{2}}

(D)

μ_{s} = 1 - \frac{1}{n ^{2}}

JEE Main 2020, 3 Sep Shift-II

LEVELJEE Advanced

A block starts moving up an inclined plane of inclination $3 0^{\circ}$ with an initial velocity of $v_{0}$ . It comes back to its initial position with velocity $\frac{v _{0}}{2}$ . The value of the coefficient of kinetic friction between the block and the inclined plane is close to $\frac{I}{1000}$ , the nearest integer to $I$ is .......... .

JEE Main 2019, 9 Jan Shift-I

LEVELJEE Advanced

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 F, such that the block does not move downward ? (Take, $g = 10 ms^{- 2}$ )

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 $F$ as shown in figure. 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 in block $B$ is

(A)

100 N

(B)

80 N

(C)

120 N

(D)

150 N

JEE Main 2021, 18 March Shift-II

LEVELJEE Advanced

A solid cylinder of mass $m$ is wrapped with an inextensible light string and, is placed on a rough inclined plane as shown in the figure. The frictional force acting between the cylinder and the inclined plane is (The coefficient of static friction, $μ_{s}$ , is 0.4)

(A)

\frac{7}{2} m g

(B)

5 m g

(C)

\frac{m g}{5}

(D)

0

JEE Main 2019

LEVELJEE Advanced

A block kept on a rough inclined plane, as shown in the figure, remains at rest upto a maximum force $2 N$ down the inclined plane. The maximum external force up the inclined plane that does not move the block is $10 N$ . The coefficient of static friction between the block and the plane is (Take, $g = 10 m/s^{2}$ )

(A)

\frac{2}{3}

(B)

\frac{3}{2}

(C)

\frac{3}{4}

(D)

\frac{1}{2}

JEE Main 2018

LEVELJEE Main

Two masses $m_{1} = 5 kg$ and $m_{2} = 10 kg$ connected by an inextensible string over a frictionless pulley, are moving as shown in the figure. The coefficient of friction of horizontal surface is $0.15$ . The minimum weight $m$ that should be put on top of $m_{2}$ to stop the motion is

JEE Main 2019, 12 April Shift-II

LEVELJEE Main

A block of mass $5 kg$ is (i) pushed in case (A) and (ii) pulled in case (B), by a force $F = 20 N$ , making an angle of $3 0^{\circ}$ with the horizontal, as shown in the figures. The coefficient of friction between the block, the floor is $μ = 0.2$ . The difference between the accelerations of the block, in case (B) and case (A) will be (Take, $g = 10 ms^{- 2}$ )

(A)

0.4 ms^{- 2}

(B)

3.2 ms^{- 2}

(C)

0.8 ms^{- 2}

(D)

0 ms^{- 2}

JEE Main 2021

LEVELJEE Advanced

When a body slides down from rest along a smooth inclined plane making an angle of $3 0^{\circ}$ with the horizontal, it takes time $T$ . When the same body slides down from the rest along a rough inclined plane making the same angle and through the same distance, it takes time $α T$ , where $α$ is a constant greater than 1. The coefficient of friction between the body and the rough plane is $\frac{1}{x} (\frac{α ^{2} - 1}{α ^{2}})$ , where $x$ is ......... .

JEE Main 2021, 17 March Shift-II

LEVELJEE Main

A boy of mass $4 kg$ is standing on a piece of wood having mass $5 kg$ . If the coefficient of friction between the wood and the floor is $0.5$ , the maximum force that the boy can exert on the rope, so that the piece of wood does not move from its place is ............... N. (Round off to the nearest integer) (Take, $g = 10 ms^{- 2}$ )

LEVELJEE Main

Consider a car moving on a straight road with a speed of $100 ms^{- 1}$ . The distance at which car can be stopped, is $[μ_{k} = 0.5]$

JEE Main 2021, 20 July Shift-II

LEVELJEE Advanced

A body of mass $m$ is launched up on a rough inclined plane making an angle of $3 0^{\circ}$ with the horizontal. The coefficient of friction between the body and plane is $\frac{x}{5}$ . If the time of ascent is half of the time of descent. The value of $x$ is .......

LEVELJEE Main

A marble block of mass $2 kg$ lying on ice when given a velocity of $6 ms^{- 1}$ is stopped by friction in $10 s$ . Then, the coefficient of friction is

(A)

0.02

(B)

0.03

(C)

0.06

(D)

0.01

LEVELJEE Main

A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is

JEE Main 2021, 16 March Shift-I

LEVELJEE Main

A block of mass $m$ slides along a floor, while a force of magnitude $F$ is applied to it at an angle $θ$ as shown in figure. The coefficient of kinetic friction is $μ_{k}$ . Then, the block's acceleration $a$ is given by ( $g$ is acceleration due to gravity)

(A)

- \frac{F}{m} cos θ - μ_{k} (g - \frac{F}{m} sin θ)

(B)

\frac{F}{m} cos θ - μ_{k} (g - \frac{F}{m} sin θ)

(C)

\frac{F}{m} cos θ - μ_{k} (g + \frac{F}{m} sin θ)

(D)

\frac{F}{m} cos θ + μ_{k} (g - \frac{F}{m} sin θ)

JEE Main 2021, 26 Aug Shift-II

LEVELJEE Advanced

The coefficient of static friction between two blocks is 0.5 and the table is smooth. The maximum horizontal force that can be applied to move the blocks together is .......N. (Take, $g = 10 ms^{- 2}$ )

LEVELJEE Main

The minimum force required to start pushing a body up a rough (frictional coefficient $μ$ ) inclined plane is $F_{1}$ while the minimum force needed to prevent it from sliding down is $F_{2}$ . If the inclined plane makes an angle $θ$ from the horizontal such that $tan θ = 2 μ$ , then the ratio $F_{1} / F_{2}$ is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Consider a car moving on a straight road with a speed of 100 ms−1. The distance at which car can be stopped, is [μk​=0.5]

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A marble block of mass 2 kg lying on ice when given a velocity of 6 ms−1 is stopped by friction in 10 s. Then, the coefficient of friction is

A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is

Consider a car moving on a straight road with a speed of $100 ms^{- 1}$ . The distance at which car can be stopped, is $[μ_{k} = 0.5]$

A marble block of mass $2 kg$ lying on ice when given a velocity of $6 ms^{- 1}$ is stopped by friction in $10 s$ . Then, the coefficient of friction is