A particle of mass $m$ at rest is acted upon by a force $F$ for a time $t$. Its Kinetic energy after an interval $t$ is
$\frac{{{F^2}{t^2}}}{m}$
$\frac{{{F^2}{t^2}}}{{2m}}$
$\frac{{{F^2}{t^2}}}{{3m}}$
$\frac{{F\,t}}{{2m}}$
Two bodies of masses $m$ and $4 \,m$ are moving with equal $K.E.$ The ratio of their linear momentums is
A body of mass $2\, kg$ is thrown up vertically with K.E. of $490$ joules. If the acceleration due to gravity is $9.8$$m/{s^2}$, then the height at which the K.E. of the body becomes half its original value is given by ............ $\mathrm{m}$
Equal force $F ( > mg)$ is applied to string in all the $3$ cases. Starting from rest, the point of application of force moves a distance of $2 m$ down in all cases. In which case the block has maximum kinetic energy?
An object of mass ' $m$ ' initially at rest on a smooth horizontal plane starts moving under the action of force $F=2 N$. In the process of its linear motion, the angle $\theta$ (as shown in figure) between the direction of force and horizontal varies as $\theta= kx$, where $k$ is a constant and $x$ is the distance covered by the object from its initial position. The expression of kinetic energy of the object will be $E =\frac{ n }{ k } \sin \theta$. The value of $n$ is $.....$
The bob of a simple pendulum (mass m and length $ l$) dropped from a horizontal position strikes a block of the same mass elastically placed on a horizontal frictionless table. The K.E. of the block will be