Work-energy-power practice · Mixed difficulty

A rubber ball is dropped from a height of 5 m on a planet, where the acceleration due to gravity is not known. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of

The kinetic energy of particle continuously increase with time
a. The resultant force on the particle must parallel to velocity at all instants
b. The resultant force on the particle at an angle less than $90^{\circ}$ all the time
c. Its height above the ground level continuously decrease
d. The magnitude of its linear momentum is increasing continuously

If the linear momentum is increased by $40 \%$, then kinetic energy will be increased by

Choose the incorrect statement

When work done on a particle is positive
a) K.E remains constant
b) Momentum increases
c) K.E increases
d) K.E decreases

A weightless thread can bear tension upto 37 N. A stone of mass 500 g is tied to it and revolved in a circular path of radius 4 m in a vertical plane. $\mathrm{If\;g} = 10\mathrm{\;m}{\mathrm{s}^{ - 2}},$ then the maximum angular velocity of the stone will be

A man is standing on a stationary car of mass $m$ placed on a smooth rail. The man starts walking with velocity $v$ relative to car. Find the mass of the man if work done by him when he moves along the rails is same when he walks normal to the rails

Velocity vector and acceleration vector in a uniform circular motion are related as

When two bodies collide elastically, the force of interaction between them is

In a simple pendulum of length $10 \mathrm{~m}$, string is initially kept horizontal and the bob is released. $10 \%$ of energy is lost till the bob reaches lowermost position. Then find speed of bob at lowermost position.

A body is tied to one end of the string and whirled in a vertical circle, the physical quantity which remains constant is

A body of mass 50 kg is projected vertically upwards with velocity of 100 m/sec. 5 seconds after this body breaks into 20 kg and 30 kg. If 20 kg piece travels upwards with 150 m/sec, then the velocity of the block will be

If kinetic energy of a body is increased by $300 \%$ than percentage change in momentum will be

If two persons $A$ and $B$ takes 2 seconds and 4 seconds respectively to lift an object to the same height $h$ then ratio of their power is

A force of 5N, making an angle $\theta$ with the horizontal, acting on an object displaces it by 0.4m along the horizontal direction. If the object gains kinetic energy of 1J, the horizontal component of the force is

Statement-I: If collision occurs between two elastic bodies their kinetic energy decreases during the time of collision.
Statement-II: During collision intermolecular space decreases and hence elastic potential energy increases.

In uniform circular motion, the velocity vector and acceleration vector are

A body of mass m kg is lifted by a man to a height of one metre in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them are in the ratio

From a building two balls A to B are thrown such that A is thrown upwards and B downwards (both vertically). If ${v_A}$ and ${v_B}$ are their respective velocities on reaching the ground, then

A body is moving with a constant speed $v$ in a circle of radius $r$. Its angular acceleration is

Sand is falling on a conveyor belt at rate of 6 kg/s. The extra power required to move the belt with a velocity of 5 m/s is

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

One sphere collides head-on with another sphere of double the mass at rest. If $e$ is the coefficient of restitution between them then the ratio of their respective speeds after collision 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

A person pushes a box on a rough horizontal platform surface. He applies a force of 200 N over a distance of 15 m. Thereafter, he gets progressively tired and his applied force reduces linearly with distance to 100 N. The total distance through which the box has been moved is 30 m. What is the work done by the person during the total movement of the box?