Class 11th

The height at which the weight of an object becomes (1/16)^th of its weight on the surface of earth is (R is radius of earth)

A body is released from height equal to radius R of the earth. The velocity of body with which it will strike the earth surface is

Two bodies of mass 10 kg and 2 kg are moving with velocities m/s and  m/s respectively. The velocity of their centre of mass is

In stable equilibrium position, a body has

A particle moves along x axis from x = 1 m to x = 3 m under the effect of the force F = 3x² – 2x + 5 N. Work done in process is

A mass of 1 kg is suspended by a thread. It is lifted up with an acceleration of 4.9 ms^–2, and then lowered with an acceleration of 4.9 ms^–2 . The ratio of tensions in first case to second cases is (g = 9.8 ms^–2 )

A block rests on an inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between block and the plane is 0.8. If the frictional force on the block is 10 N, then mass of block (in kg) (Take g = 10 m/s² )

Bullets of 0.03 kg mass each hit a plate at a rate of 200 bullets per second with velocity of 50 m/s and reflect back with velocity of 30 m/s. The average force acting on the plate in newton is

In the equation of angular displacement of a particle moving on a circular path is given as is in radian and t in second. Theq angular velocity of the particle at t = 2 s is

A ball is projected from ground at angle q with the horizontal. After t = 1 s, it is moving at 45° with the horizontal and after t = 2 second, it is moving horizontally. What is speed of projection of ball? [g = 10 m s^–2]