Embibe Experts Solutions for Chapter: Work, Energy and Power, Exercise 6: Exercise (Previous Year Questions)

The potential energy of a system increases, if work is done

The potential energy of a particle in a force field is $U=\frac{A}{r^2}-\frac{B}{r}$ where $A$ and $B$ are positive constants and $r$ is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is

A particle of mass $\mathrm{m}$ is driven by a machine that delivers a constant power $k$ watts. If the particle starts from rest, the force on the particle at time $t$ is

The heart of a man pumps $5\mathrm{L}$ of blood through arteries per minute at a pressure of $150\mathrm{mm}$ of mercury. If the density of mercury $13·6\times {10}^3\mathrm{kg}/{\mathrm{m}}^3$ and $g=10\mathrm{m}/{\mathrm{s}}^2$, then power of the heart in watt is 

A particle moves from a point $(-2\hat{i}+5\hat{j})\mathrm{m}$ to $(4\hat{j}+3\hat{k})$ when a force of $(4\hat{i}+3\hat{j})\mathrm{N}$ is applied. How much work has been done by the force?

Consider a drop of rain water having mass $1 g$ falling from a height of $1 km.$ It hits the ground with a speed of $50 m/s.$ Takes $g$ constant with a value of $10 m/s^2$. The work done by the 
$\left(i\right)$ Gravitational force and the  $\left(ii\right)$ resistive force of air is 

A particle of mass $10 \mathrm{g}$ moves along a circle of radius $6.4 \mathrm{cm}$ with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to $8\times {10}^{-4} \mathrm{J}$ by the end of the second revolution after the beginning of the motion ?

What is the minimum velocity with which a body of mass m must enter vertical loop of radius $R$ so that it can complete the loop?