The potential energy of a particle of mass 0.5 kg moving along x axis is given by
U = 2x (x - 3). The speed of the particle is maximum at
(1) x = 1 m
(2) x = 1.5 m
(3) X = 2 m
(4) x = 3 m
A ball strikes the floor at an angle of with vertical and rebounds of an angle of 60° with the vertical. Assuming the contact to be smooth the coefficient of restitution is
1. 1
2.
3.
4.
Work energy theorem is valid in
(1) Only inertial frame of reference
(2) The only non-inertial frame of reference
(3) Both inertial and non-inertial frame of reference
(4) Does not depend on any frame of reference
A block of mass m is projected with speed v along the rough surface of an inclined plane of height h. If block comes to rest at the top of the surface, then work done by friction force is
1.
2.
3. -mgh
4.
A body of mass m moving with speed v collides head-on elastically with another identical body at rest. The percentage loss in kinetic energy of the first body will be:
1. | 0% | 2. | 25% |
3. | 50% | 4. | 100% |
If a body starts its motion along the smooth track from P as shown in the figure, then its velocity at the instant of leaving R is
(1) 5 m/s
(2) 15 m/s
(3) 10 m/s
(4) 20 m/s
The principle of conservation of energy and conservation of mechanical energy applicable respectively for
(1) Conservative and non-conservative forces
(2) Conservative and conservative force
(3) Non-conservative and conservative forces
(4) All forces and conservative forces
A ball of mass 2 kg is at rest on a horizontal smooth surface. Another ball of the same mass hit the first ball at an angle of 60° with the horizontal. At the time of the collision, the velocity of the second ball is 20 m/s. If the collision is perfectly inelastic and after the collision, both the balls stick together, then the speed of the combined balls is:
(1) Zero
(2) 2.5 m/s
(3) 10 m/s
(4) 5 m/s
A particle of mass m is moving in a vertical circle of radius r. If the velocity of the particle at the uppermost point is , then its velocity at the lowermost point
(1)
(2)
(3)
(4) 2
A bullet is fired from a gun. Assuming that the gun recoils freely, the kinetic energy of the bullet is
(1) less than the kinetic energy of the gun.
(2) equal to the kinetic energy of the gun.
(3) more than the kinetic energy of the gun.
(4) equal to or less than the kinetic energy of the gun.