Work-energy-power practice · Mixed difficulty

A bullet of mass m moving with velocity v strikes a suspended wooden block of mass M. If the block rises to a height h, the initial velocity of the block will be

A sphere collides with another sphere of identical mass. After collision, the two spheres move. The collision is inelastic. Then the angle between the directions of the two spheres is

Assertion: No work is done by a force on an object when the point of application of the force does not move.
Reason: A small block of mass $m$ is kept on a rough inclined surface of inclination $a$ fixed in an elevator. The elevator goes up with a uniform velocity $u$ and the block does not slide on the wedge. Then the work done by the force of friction on the block in time $t$ will be $mgut \sin ^2 \alpha$.

Statement-1: A body can have energy without having momentum and vice versa.
Statement-2: The body having momentum must necessarily have kinetic energy.

Statement I A cyclist is moving on an unbanked road with a speed of $7\,km{h^{ - 1}}$ and takes a sharp circular turn along a path of radius of 2 m without reducing the speed. The static friction coefficient is 0.2. The cyclist will not slip and pass the curve $\left( {g\, = \,9.8\,m/{s^2}} \right)$
Statement II If the road is banked at an angle of ${45^\mathrm{o}}$, cyclist can cross the curve of 2 m radius with the speed of $18.5\,km{h^{ - 1}}$ without slipping.
In the light of the above statements, choose the correct answer from the options given below.

Which of the following is not a conservative force

The potential energy of a body (U) of mass 1 kg varies with position co-ordinates of the particle x (m) and y (m) as $U = \mathrm{ }4x + \mathrm{ }3y$. The acceleration of the particle is

A variable force, given by the 2-dimensional vector $\vec F = \left( {3{x^2}\hat i + 4\;\hat j} \right)$, acts on a particle. The force is in newton and x is in metre. What is the change in the kinetic energy of the particle as it moves from the point with coordinates (2,3) to (3,0) (The coordinates are in metres)

In which case does the potential energy decrease

Which among the following is a form of energy

The area under the displacement-force curve gives

A ping-pong ball strikes a wall with a velocity of 12 m/s if the collision is perfectly elastic, find the velocity of ball after impact?

If KE of the particle of mass m performing UCM in a circle of radius r is E. Find the acceleration of the particle

Consider the following two statements 1. Linear momentum of a system of particles is zero 2. Kinetic energy of a system of particles is zero, Then

A body of mass 1 kg is moving in a vertical circular path of radius 1 m. The difference between the kinetic energies at its highest and lowest point is

If a lighter body (Mass ${M_1}$ and velocity ${V_1}$) and a heavier body (mass ${M_2}$ and velocity ${V_2}$) have the same kinetic energy, then

When a force is applied on a moving body, its motion is retarded. Then the work done is

A time t=0 s Particle starts moving along the x-axis. If its kinetic energy increases uniformly with time t, the net force acting on it must be proportional to

A boy carrying a box on his head is walking on a level road from one place to another on a straight road is doing no work. The statement is

Assertion: Collision between two billiard's ball is inelastic
Reason: Momentum remains conserve during the collision

The total energy of the universe is

The kinetic energy possessed by a body of mass m moving with a velocity v is equal to $1/2\;m{v^2}$, provided

If momentum of a body is increased by $20 \%$, then its kinetic energy increases by

There will an increase in potential energy of the system, if work is done upon the system by

The minimum speed for a particle at the lowest point of a vertical circle of radius r, to describe the circle is $v$. If the radius of the circle is reduced to one-fourth its value, the corresponding minimum speed will be

The work done in lifting a body mass of 20 kg and specific gravity 3.2 to a height of 8 m in water is

Consider a one dimensional head on collision of two balls.
Statement-1: The loss in kinetic energy of the system during the collision does not depend on the velocity of the observer.
Statement-2 : Kinetic energy of a body is independent of velocity of observer.

Which of the following is a unit of energy

The bodies of masses 1 kg and 5 kg are dropped gently from the top of a tower. At a point 20 cm from the ground, both the bodies will have the same

A body is acted upon by a constant force directed towards a fixed point. The magnitude of the force varies inversely as the square of the distance from the fixed point. What is the nature of the path?