Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Friction in Solids and Liquids, Exercise 2: Critical Thinking

A vehicle of mass $m$ is moving on a rough horizontal road with momentum $P$. If the coefficient of friction between the tyres and the road be $\mu \mathit{,}$ then the stopping distance is

A $60 \mathrm{kg}$ body is pushed with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are $0.5$and $0.4$ respectively. The acceleration of the body is

A ball of radius $r$ and density $\rho$ falls freely under gravity through a distance h before entering the water. The velocity of the ball does not change even on entering water. $\eta ,$If viscosity of water is the value of $h$ is given by

In the houses far away from the municipal water tanks often water does not rise to the top floor. This happens because

A plane is in level flight at constant speed and each of its two wings has an area of $20 {\mathrm{m}}^2$. If the speed of the air is $180 \mathrm{km} {\mathrm{h}}^{-1}$ over the lower wing and $216 \mathrm{km} {\mathrm{h}}^{-1}$ over the upper wing surface, determine the plane's mass. (Take air density to be $1 {\mathrm{kgm}}^{-3}$ and $\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}$).

For a fluid in a steady flow, the increase in flow speed at a constriction follows

A cylindrical tank is filled with water to a level of $4 \mathrm{m}.$ A hole is opened at a height of $60 \mathrm{cm}$ from bottom. The ratio of the area of the hole to that at a cross-sectional area at cylinder is $0.2.$ Then the velocity with which water is coming out is $\left(g=10\mathrm{m} {\mathrm{s}}^{-2}\right)$

Assertion: The acceleration of a body down a rough inclined plane is greater than the acceleration due to gravity.

Reason: The body is able to slide on an inclined plane only when its acceleration is greater than the acceleration due to gravity.