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

Statement-1: It is easier to pull a heavy object than to push it on a level ground.

Statement-2: The magnitude of frictional force depends on the nature of the two surfaces in contact.

A smooth block is released from rest on a $45°$ incline and then, it slides a distance $d$. The time taken to slide is $n$ times as much to slide on a rough incline than on a smooth incline. The coefficient of friction is,

Consider a car moving on a straight road with a speed of $100 \mathrm{m} {\mathrm{s}}^{-1}.$ The distance at which car can be stopped is $[{\mu }_{\mathrm{k}}=0.5$, $g=10 \mathrm{m} {\mathrm{s}}^{-2}$]

The minimum force required to start pushing a body up a rough (frictional coefficient $\mu$ ) 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 $\theta$ with the horizontal such that $\tan \theta =2\mu$, then the ratio $\frac{F_1}{F_2}$ is

A block of mass$m$ is placed on a surface with a vertical cross-section given by $Y=\frac{X^3}{6}$ If coefficient of friction between the block and the surface is $0.5,$ what is the maximum height above ground at which block can be placed without slipping?

Given in the figure are two blocks $A$ and $B$ of weight $20 \mathrm{N}$ and $100 \mathrm{N}$, respectively. These are being pressed against a wall by a force $F$ 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 (assume system in equilibrium):

Two masses $m_1=5 \mathrm{kg}$ and $m_2=10 \mathrm{kg}$ 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:

A block of base $10 \mathrm{cm}\times 10 \mathrm{cm}$ and height $15 \mathrm{cm}$ is kept on an inclined plane. The coefficient of friction between them is $\sqrt{3}$. The inclination $\mathrm{\theta }$ of this inclined plane from the horizontal plane is gradually increased from $0°$. Then