Forces and Laws...

Four alternatives are given to the following incomplete statement/question. Choose the right answer.
If the forces acting on an object are balanced then 

What is the momentum of an object of mass m, moving with a velocity $$V$$ ?

Newton’s second law of motion says that the mass of object times its acceleration is equal to the net force on the object. Which of the following gives the correct units for force?

A body of mass $$10\ kg$$ undergoes a change in velocity of $$10\ m/s$$ in $$5\ s$$. What is the force acting on it?

In the above figure, a locomotive has broken through the wall of a train station. During the collision, what can be said about the force exerted by the locomotive on the wall?

An athlete jumps straight up in the air to catch a ball. If he took $$0.4$$ seconds to jump up and $$0.4$$ seconds to come back down, how high did he jump? Take $$g = 9.8\ m/s^{2}$$.

Which of these examples can be explained by Newtons first law of motion ?

A bullet of mass A and velocity B is fired into a block of wood of mass C. If loss of any mass and friction be neglected, then velocity of the system must be

 A shell of mass 100 g moving with the speed of $$50 m s^{-1}$$ along a straight line bursts into two pieces. The piece of mass 60 g starts moving horizontally with a speed of $$50 m s^{-1}$$. The other piece moves with a speed of

When a bus starts suddenly, the passengers are pushed back. This is an example of which of the following?