Embibe Experts Solutions for Chapter: Friction, Exercise 2: Exercise-2

A block $A$ is placed over a long rough plank $B$ of same mass as shown in figure. The plank is placed over a smooth horizontal surface. At time $t=0$, block $A$ is given a velocity $v_0$ in horizontal direction. Let $v_1$ and $v_2$ be the velocities of $A$ and $B$ at time $t$. Then choose the correct graph between $v_1$ or $v_2$ and $t$.

Three blocks $A, B$ and $C$ of equal mass $m$ are placed one over the other on a smooth horizontal ground as shown in figure. Coefficient of friction between any two blocks of $A, B$ and $C$ is $\frac{1}{2}$. The maximum value of mass of block $D$ so that the blocks $A, B$ and $C$ move without slipping over each other is

A block is placed over a plank. The coefficient of friction between the block and the plank is $\mathrm{\mu }=0.2$. Initially both are at rest, suddenly the plank starts moving with acceleration $a_0=4 \mathrm{m} {\mathrm{s}}^{-2}$. The displacement of the block in $1 \mathrm{s}$ is $\left(\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$

Two blocks of masses ${\mathrm{m}}_1$ and ${\mathrm{m}}_2$ are connected with a massless spring and placed over a plank moving with an acceleration '$\mathrm{a}$' as shown in figure. The coefficient of friction between the blocks and platform is $\mathrm{\mu }$.

A sphere is placed rotating along its centre and initially at rest in a comer as shown in figure $\left(A\right) \text{\&} ( B)$. The coefficient of friction between all surfaces and the sphere is $\frac{1}{3}$. Find the ratio of the frictional force $\frac{f_A}{f_B}$ by ground in situations $\left(A\right) \text{\&} \left(B\right)$ is:

A plank with a uniform sphere placed on it, rests on a smooth horizontal plane. Plank is pulled to right by a constant force $F$. If the sphere does not slip over the plank then 

If a cylinder is rolling down the incline with sliding