A machine gun of mass 20 kg fires 35 gram bullet at the rate of 50 bullets per second with a speed of 400 `m s^-1`. What force must be applied to the gun to keep it in position?

A machine gun of mass M fires n bullets per second .The mass and speed of each bullet is m and v respectively. Then force exerted on the machine gun is :

A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m s^-1 , what is the recoil speed of the gun ?

A police van moving on a highway with a speed of 30 km h^-1 fires a bullet at a thiefs car speeding away in the same direction with a speed of 192 km h^-1 . If the muzzle speed of the bullet is 150 m s^-1 with what speed does the bullet hit the thiefs car ? (Note: Obtain that speed which is relevant for damaging the thief s car).

A trolley of mass 200 kg moves with a uniform speed of 36 km//h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 m s^-1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley ? How much has the trolley moved from the time the child begins to run ?

A bullet of mass 20 g is fired with speed 400 m s^-1 by a gun of mass 8 kg. Find the recoil velocity of the gun.

A man of mass 70 kg stands on a weighing scale in a lift which is moving :- upwards with a uniform speed of 10 m s^-1 , what would be the reading on scale?

A bullet of mass 50 g is fired from a gun. If the bullet acquires a velocity of 100 m s^(1) in 0.1 second, what is the recoil force on the gun?

A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m s^-1 . It hits the floor of the elevator (length of the elevator = 3 m) and does not rebound. What is the heat produced by the impact ? Would your answer be different if the elevator were stationary ?

A 15 g bullet is fired from a gun of mass 3 kg speed of bullet just after firing is 300 ms^-1 . The recoil speed of gun.