Physics Test 79...

A block of mass 2kg is  suspended by a light string from the ceiling of a lift. The lift starts moving down with an acceleration a = 1.8 m/s². Find the work done by tension in the string during the first 5 seconds.

A bullet moving with a speed of 100 m/sec travels a distance of 2cm in a plank of wood before coming to rest. How much distance will the same bullet travel in the same plank before coming to rest if it were moving with a speed of 200 m/sec ?

A mass m, lying on a horizontal frictionless surface is connected to a mass M as shown in figure. The system is now released. The velocity of mass m when mass M discends a distance h is

A body of mass 5 kg rests on a rough horizontal surface of coefficient of friction 0.2. The body is pulled through a distance of 10m by a horizontal force of 25N. The kinetic energy acquired by it is (g = 10 m/s²)

A particle is released from rest at origin. It moves under the influence of potential field U = x² – 3x. Kinetic energy of particle at x = 2 is

A block begins to move on a rough horizontal surface with an initial velocity 'u'. If it loses 1/4 of its initial kinetic energy in time 't', the coefficient of kinetic friction between the block and the surface is 

Kinetic energy of a particle moving in a straight line varies with time t as K = 4t². The force acting on the particle

A particle is projected with a velocity u making an angle θ with the horizontal. The instantaneous power of the gravitational force

Force  where x in meter, acts on a particle. Work done on the particle as it moves from coordinates (2m, 3m) to (3m, 0m) is

In the diagram shown all surfaces are smooth. If the system is released from rest with spring un stretched. Then the maximum extension in the spring will be