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WHAT IS ACTUALLY MOMENTUM? TEACHER SAYS,'P IS THE PRODUCT OF M AND V...' I DIDNOT UNDERSTAND THIS! U KNOW A FACT ...I HATE PHYSICS 2.. WHAT SHOULD I DO 2 CHANGE THIS IMPRESSION?
We know that a cricket ball is much  more heavy than a tennis ball. Suppose we throw a cricket ball and a tennis ball, both with the same speed or velocity. It will be found that  more force is required to stop the cricket ball (which has more mass) and less force is required to stop the tennis ball (which has less mass ).We conclude that the force required to stop a moving body is directly proportional to its mass. Now, if we throw two cricket balls of the same mass at different speeds or velocities, it will be found that more force is required to stop that cricket ball which is moving with higher velocity and less force is required to stop the cricket ball moving with lower velocity. So we conclude that the force required to stop a moving body is also directly proportional to its velocity. Thus, the quantity of motion in a body depends on the mass and velocity of the body. 
This gives the term known as ”MOMENTUM”. The momentum of a body is defined as the product of its mass and velocity. Momentum is denoted by the letter ‘p’.
Thus,           Momentum = mass x velocity
     Or,                   p = m x v
Where p = momentum
             m = mass
             v = velocity (or speed) of the body
It is clear that if a body is at rest, its velocity is zero and hence its momentum is also zero. Thus, the total momentum of the gun and bullet before firing is zero because their velocity is zero. Momentum is a vector quantity. We know that mass is measured in kilograms (kg) and velocity is measured in meters per second (m/s), so the S.I unit of momentum is kilogram meters per second which is written as kg.m/s or kg .ms-1   .
Every moving body possesses momentum. Since momentum depends on the mass and velocity of a body, so a body will have a large momentum (a)if its mass is large, or (b) if its velocity is large ,or (c) if both its mass and velocity (speed) are large.
Let’s discuss one of the everyday situations which involve large momentum. A karate player can break  a pile of tiles or a slab of ice with a single blow of his hand. This is because a karate player strikes the pile of tiles or the slab of ice with his hand very, very fast. In doing so , the large momentum of the fast moving hand is reduced to zero in a very ,very short time. This exerts a very large force on the pile of tiles or the ice slab which is sufficient to break them apart.



Physics is a very nice subject.It is a subject based on experimental , observative and quantitative measurement.Sojust listen and understand what the teacher says.


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