Forces and Laws...

A man and a cart move towards each other. The man weighs 64 kg and the cart 32 kg. The velocity of the man is 5.4 km/hr and that of the cart is 1.8km/hr. When the man approaches the cart, he jumps on to it. The velocity of the cart carrying the man will be:

The net force on a rocket with a weight of $$1.5\times 10^{4}N$$ is $$2.4 \times 10^{4}N$$. About how much time is needed to increase the rocket's speed from $$12 m/s$$ to $$36 m/s$$ near the surface of the Earth at take off? (Take $$g=10m/s^2$$)

A $$60 \ kg$$ boy lying on a surface of negligible friction throws a stone of mass $$1 \ kg$$ horizontally with a speed of $$12 \ m/s$$ away from him. With what kinetic energy does he move back due to result of this action?

When a gun of mass $$M$$ fires a bullet of mass $$m$$, the total energy released in the explosion is found to be $$E$$. The kinetic energy of the bullet is:

A man stands on the surface of the earth. The number of action reaction pairs that can be seen here is/are 

A horizontal force $$F $$ produces an acceleration of  $$6 \ m/ s^{2}$$ on a block resting on a smooth horizontal surface. The same force produces an acceleration of $$3\ m/ s^{2}$$ on a second block resting on a smooth horizontal surface. If the two blocks are tied together and the same force acts, the acceleration produced will be:

A trolley of mass $$60 kg$$ moves on a smooth horizontal surface and has kinetic energy $$120 J$$.A mass of $$40 kg$$ is lowered vertically on to the trolley. The total kinetic energy of the system after lowering the mass is:

 A boy weighing 50 kg throws a stone of mass 10 kg horizontally with a velocity of $$8 ms^{-1}$$. With what velocity does he move after throwing?

A gun fires a bullet of mass 50 g with a velocity of mass $$130$$ ms$$^{-1}$$. Because of this, the gun is pushed back with a velocity of $$1$$ ms$$^{-1}$$. The mass of the gun is :

 A bullet of mass 20 gm is fired from a rifle of mass 20 kg with a muzzle velocity of $$200\ ms^{-1}$$. Find the velocity of recoil of the rifle.