Work-energy-power practice · Medium

A body slides down a frictionless track which ends in a circular loop of diameter D. Then the minimum height h of the body in terms of D so that it may just complete the loop, is

Two identical bodies are executing uniform circular motion in the paths of radii ${r_1}$ and ${r_2}$ respectively. If both the bodies complete one revolution in the same time interval, then the ratio of their angular speeds is

Statement I Two bodies of different masses have the same momentum, and their kinetic energies are in the inverse ratio of their masses.

Statement II Kinetic energy of body is given by the relation.

${KE}=\frac{1}{2} m v^2$

A bullet is fired from a rifle. If the riffle recoils freely, then the kinetic energy of the rifle is

A particle is moving in a conservative force field from point $A$ to point $B . U_A$ and $U_B$ are the potential energies of the particle at points $A$ and $B$; and $W_C$ is the work done by conservative forces in the process of taking the particle from $A$ and $B$. Which of the following is true?

A particle moves along x-axis from x=1m to x=3m under the effect of the force $F = 3{x^2} - 2x + 5\mathrm{ }N$ work done in process is

A 2 kg block slides on a horizontal floor with a speed of 4 m/s. It strikes a uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is 15 N and spring constant is 10,000 N/m. The spring compresses by

This question has Statement I and Statement II. Of the four choices given after the statements, choose the one that best describes the two statements.

Statement I A point particle of mass $m$ moving with speed $v$ collides with stationary point particle of mass $M$ . If the maximum energy loss possible is given as $f\left( {\frac{1}{2}m{v^2}} \right),\,$ then $f = \left( {\frac{m}{{M + m}}} \right)$

Statement II Maximum energy loss occurs when the particles get stuck together as a result of the collision.

A particle is moving in a horizontal circle with constant speed. It has constant

Consider the following statements A and B identify the correct choice in the given answers
A) In a one-dimensional perfectly elastic collision between two moving bodies of equal masses, the bodies exchange their velocities after the collision
B) If a lighter body at rest suffers head-on and perfectly elastic collision with a very heavy body moving with a certain velocity, after the collision both travel with same velocity

Statement-I: The normal force on a body by the floor is not a conservative force
Statement-II: The normal force does no work at all. Hence it will not store energy in the system.

The area of the acceleration-displacement curve of a body gives

Consider the following statements. A and B and identify the correct answer given below. I. Body initially at rest is acted upon by a constant force. The rate of change of its kinetic energy varies linearly with time. II. When a body is at rest, it must be in equilibrium.

A particle is moving on a circular path with constant speed, then its acceleration will be

A steel ball of mass 5 g is thrown downward with velocity $10\;\mathrm{m}{\mathrm{s}^{ - 1}}$ from height 19.5 m. It penetrates sand by 50 cm. The change in mechanical energy will be $\left( {\mathrm{g} = 10\,\,\mathrm{m}{\mathrm{s}^{ - 2}}} \right)$

Two bodies A and B of definite shape (dimensions of bodies are not ignored). A is moving with speed of 10 $\mathrm{m}{\mathrm{s}^{ - 1}}$ and B is in rest, collide elastically. The

When a body moves with some friction on a surface

A 1 kg block moving with velocity of 4 m/s collides with stationary 2 kg block. The lighter block comes to rest after collision. The loss of kinetic energy of the system is

A man, by working a hand pump fixed to a well, pumps out $10\mathrm{\;}{\mathrm{m}^3}$ water in 1 s. If the water in the well is 10 m below the ground level, then the work done by the man is $\left( {\mathrm{g} = 10\mathrm{m}{\mathrm{s}^{ - 2}}} \right)$

Two observers are situated in different inertial reference frames. Then

The potential energy function for the force between two atoms in a diatomic molecule is approximately given by $U\left( x \right)\frac{a}{{{x^{12}}}}\; - \frac{b}{{{x^6}}}$ ,where a and b are constants and x is the distance between the atoms , If the dissociation energy of the molecule is $D = \left[ {U\left( {x = \infty } \right) - {U_{\mathrm{at\,\,equilibrium}}}} \right],D$ is

If the linear momentum is increased by $50\%$, then kinetic energy will be increased by

The decrease in the potential energy of a ball of mass 20 kg which falls from a height of 50 cm is

If the coefficient of restitution is 0.5, what is the percentage loss of energy on each rebounding of a ball dropped from a height?

A particle moves in a circular orbit of radius r under a central attractive force $F = - \frac{k}{r}$, k is constant. The time period of its motion is proportional to

The ratio of angular speeds of the minutes hand and the hours hand of a watch is

The work done by a force $\overrightarrow F = - \left( {4{x^3}\hat i} \right)$ N is displacing a particle from x=3m to x=-1m is

Potential energy is also called as

The potential energy of a certain spring when stretched through a distance s is 10 J. The amount of work (in joule) that must be done on this spring to stretch it through additional distance s will be

What energy does a stretched bow possess?