Work, Power & Energy — JEE Main PYQs

A ball of mass 0.2 kg is thrown vertically upwards by applying a force by hand. If the hand moves 0.2 m which applying the force and the ball goes upto 2 m height further, find the magnitude of the force. Consider $g=10\mathrm{m}/{\mathrm{s}}^2$

Two insulating plates are both uniformly charged in such a way that the potential difference between them is $V_2-V_1=20\mathrm{V}$. (i.e. plate 2 is at a higher potential). The plates are separated by $d=0.1\mathrm{m}$ and can be treated as infinitely large. An electron …

The potential energy of a 1 kg particle free move along the x-axis is given by

The total mechanical energy of the particle 2 J. Then, the maximum speed (in $\mathrm{m}/\mathrm{s}$) is

The upper half of an inclined plane with inclination $\varphi$ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is given by

A bullet fired into a fixed target loses half of its velocity after penetrating 3 cm. How much further it will penetrate before coming to rest assuming that it faces constant resistance to motion?

A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m . It rolls down a smooth surface to the ground, then climbs up another hill of height 30 m and finally rolls down to a horizontal base at a height of 20 m above the ground. The velocity attained by …

The block of mass M moving on the frictionless horizontal surface collides with a spring of spring constant K and compresses it by length L. The maximum momentum of the block after collision is

A body of mass $m$ is accelerated uniformly from rest to a speed $v$ in a time $T$. The instantaneous power delivered to the body as a function time is given by

A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to

A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?

A force $\vec{F}=(5\hat{i}+3\hat{j}+2\hat{k})\mathrm{N}$ is applied over a particle which displaces it from its origin to the point $\vec{r}=(2\hat{i}-\hat{j})\mathrm{m}$. The work done on the particle in joules is

A body of mass m, accelerates uniformly from rest to ${\mathrm{v}}_1$ in time ${\mathrm{t}}_1$. The instantaneous power delivered to the body as a function of time $t$ is

A charged particle q is shot towards another charged particle Q which is fixed, with a speed $v$ it approaches $Q$ upto a closest distance $r$ and then returns. If $q$ were given a speed $2v$, the closest distances of approach would be