A `10` g bullet is fried at a plank od wood with a speed of `200m//s`. After passing through the plank which is `1.0` m thick the speed of the bullet reduces to `100m//s`. Find the average resistance offered by the plank.

A bullet weighing 10 g is fired with a velocity of 800 ms^(-1) . After passing through a mud wall 1 m thick, its velocity decreases to 100 ms^(-1) . Find the average resistance offered by the mud wall.

A man travels 200 km distance with the speed of 40 m/s and next 50 km with the speed of 10 m/s . Find the average speed of man.

A bullet of mass 0.1 kg is fired with a speed of 100 m//sec , the mass of gun is 50 kg . The velocity of recoil is

A bullet of mass 0.1 kg is fired with a speed of 100 m//sec , the mass of gun is 50 kg . The velocity of recoil is

A particle is projected at an angle 60^@ with horizontal with a speed v = 20 m//s . Taking g = 10m//s^2 . Find the time after which the speed of the particle remains half of its initial speed.

Find average speed of 40m/s and 50m/s.

A bullet leaving the muzzle of a rifle barrel with a velocity v penetrates a plank and loses one-fifth of its velocity. It then strikes second plank, which it just penetrates through. Find the ratio of the thickness of the planks, supposing the average resistance to the penetration is same in both the cases.

A bullet moving with a speed of 100 m/s can just penetrate two planks of equal thickness. Now if the speed is doubled, then the number of such planks required to stop the bullet will be

truck is moving with a speed of 15 m/s. A car chasing this truck with a speed of 10 m/s fires a bullet at truck with muzzle velocity 90 km/h. The speed with which the bullet hit the truck is

A wooden plank of mass 20kg is resting on a smooth horizontal floor. A man of mass 60kg starts moving from one end of the plank to the other end. The length of the plank is 10m . Find the displacement of the plank over the floor when the man reaches the other end of the plank.