Embibe Experts Solutions for Chapter: Friction, Exercise 3: Exercise-3

Calculate the force of friction for shown situation.(Answer to one decimal place)

If the two blocks moves with a constant uniform speed then find coefficient of friction between the surface of the block $B$ and the table. The spring is massless and the pulley is frictionless (given $m_1=30\mathrm{kg}$,$m_2=40\mathrm{kg}$)

Masses $M_1,M_2$ and $M_3$ are connected by string of negligible mass which pass over massless and frictionless pulleys $P_1$ and $P_2$ as shown in fig. The masses move such that the portion of the string between $P_1$ and $P_2$ is parallel to the inclined plane and the portion of the string between $P_2$ and $M_3$ is horizontal. The masses $M_2$ and $M_3$ are $4.0\mathrm{kg}$ each and the coefficient of kinetic friction between the masses and the surfaces is $0.25$.

The inclined plane makes an angle of $37°$ with the horizontal. If the mass $M_1$ moves downwards with a uniform velocity. Find the mass of $M_1$.

A force of $100\mathrm{N}$ is applied on a block of mass $3\mathrm{kg}$ as shown in figure. The coefficient of friction between the wall and the surface of the block is $\frac{1}{4}$. Calculate frictional  force acting on the block.

A block of mass $15\mathrm{kg}$ is resting on a rough inclined plane as shown in figure. The block is tied up by a horizontal string which has a tension of $50\mathrm{N}$. Calculate the coefficient of friction between the block and inclined plane.

$12\mathrm{N}$ of force required to be applied on $A$ to slip on $B$. Find the maximum horizontal force $F$ to be applied on $B$ so that $A$ and $B$ moves together.

Block $A$ of mass $6\mathrm{kg}$ and block $X$ are attached to a rope which passes over a pulley. A force $P=50\mathrm{N}$ is applied horizontally to block $A$, keeping it in contact with a rough vertical face. The coefficients of static and kinetic friction are ${\mu }_S=0.40$ and ${\mu }_K=0.30$. The pulley is light and  frictionless. In figure, the mass of block $X$ is set so that block $A$ is on the verge of slipping upward. The mass of block $X$ is .......$\mathrm{kg}$.

The block has mass $M$ and rests on a surface for which the coefficients of static and kinetic friction are ${\mu }_s$ and ${\mu }_k$ respectively. A force $F=k{t}^2$ is applied to the cable. Velocity of block at $t=2 \sec$ is $v \mathrm{m} {\mathrm{s}}^{-1}$. Then value of $\frac{23}{v}$ is  Given: $M=24 \mathrm{kg}, k=60 \mathrm{N} {\mathrm{s}}^{-2}, {\mu }_s=0.5, {\mu }_k=0.4$