Work-energy-power practice · Mixed difficulty

During "elastic collision"
a) There is no loss of kinetic energy
b) The bodies are perfectly elastic
c) Temporarily some of the kinetic energy is used to deform the bodies
d) After collision the bodies regain the original shape keeping the total energy constant

A ball is thrown up from the earth by a person and then caught by him on its return. When the ball falls towards the earth, the ratio of kinetic energies gained by the ball $\left(K_B\right)$ and the earth $\left(K_E\right)$ is

An elastic string of unstretched length L and force constant k is stretched by a small length $x$. It is further stretched by another small length y. The work done in the second stretching is

A girl throws a ball with initial velocity $v$ at an inclination of $45^{\circ}$. The ball strikes the smooth vertical wall at a horizontal distance $d$ from the girl and after rebounding returns to her hand. What is the coefficient of restitution between wall and the ball?

A ball of mass ${m_1}$ is a moving with velocity $v$. It collides head on elastically with a stationary ball of mass ${m_2}$. The velocity of ball becomes v/3 after collision. Then the value of the ratio $\frac{{{m_2}}}{{{m_1}}}$ is

Two perfoctly elastic balls of same mass $\mathrm{m}$ are moving with velocities $\mathrm{u}_1$ and $\mathrm{u}_2$. They collide head on elastically $\mathrm{n}$ times. The kinetic energy of the system finally is:

A 10 m long iron chain of linear mass density $0.8\mathrm{\;kg\;}{\mathrm{m}^{ - 1}}$ is hanging freely from a rigid support. If $\mathrm{g} = 10\mathrm{\;m}{\mathrm{s}^{ - 2}}$, then the power required to lift the chain upto the point of support in 10 s is

Which of the following option is not correct for inelastic collision:

If F is the force required to keep a train moving at a constant speed v,the power required is

When two bodies stick after collision, the collision is known as

Which of the following statement(s) is/are correct?

I. If momentum of a body increases by $50 \%$, its kinetic energy will increase by $125 \%$.

II. Kinetic energy is proportional to square of velocity.

A heavy weight is suspended from a spring. A person raises the weight till the spring becomes slack. The work done by him is $W$. The energy stored in the stretched spring was $E$. What will be the gain in gravitational potential energy?

A stone tied to one end of rope and rotated in a circular motion. If the string suddenly breaks, then the stone travels

A Neutron's moving with a certain kinetic energy collide head on with an atom of mass number '$A$'. Find the fraction of kinetic energy retained by it

A block of mass $m$ moving with speed $v$ collides with another block of mass $2 {~m}$ at rest. The lighter block comes to rest after the collision. The coefficient of restitution is

The two moving particles collide and clump together on a smooth horizontal surface. The following statements are given below
a) Mechanical energy is conserved
b) Total energy is conserved
c) Work done by the system is positive
d) Work done by the system is negative
Choose the correct option.

A particle strikes elastically with another particle with velocity $\mathrm{V}$. After the collision, it moves with half the velocity in the same direction. Find the velocity of the second particle if it is initially at rest

A block of $200 \mathrm{~g}$ mass is dropped from a height of $2 \mathrm{~m}$ on to a spring and compresses the spring to a distance of $50 \mathrm{~cm}$. The force constant of the spring is

Assertion: The resultant acceleration of an object in circular motion is towards the centre if the speed is constant.
Reason: A vector is necessarily changed if it is rotated through an angle.

For inelastic collision between two spherical rigid bodies

A particle moving with uniform speed in a circular path maintains:

A ship weighing $0.3 \times {10^8}$ kg-wt is pulled by a force of $0.5 \times {10^5}$N through a distance of 3 m. If the ship were originally at rest and water-resistance is negligibly small, then the ship will acquire a speed of

If a motorcyclist skids and stops after
covering a distance of 15 m. The stopping
force acting on the motorcycle by the road is
100 N, then the work done by the motorcycle
on the road is

Assertion: If work done by the force depends on path then force is said to be conservative.
Reason: All the conservative forces are central force.

Assertion(A): Force applied on a block moving in one dimension is producing a constant power, then the motion should be uniformly accelerated.

Reason(R): This constant power multiplied with time is equal to the change in kinetic energy.

A cane filled with water is revolved in a vertical circle of radius 4 m and the water just does not fall down. The time period of revolution will be

Assertion (A): In case of bullet fired from gun, the ratio of kinetic energy of gun and bullet is equal to ratio of mass of bullet and gun.

Reason (R) : In firing, momentum is conserved.

The kinetic energy of a particle is 1000 joule with the mass $2 {~kg}$. Find the momentum for the particle?

Which among the following remains conserved in all types of collisions?

In stable equilibrium position, a body has