mechanism Impulse Momentum

Momentum and Conservation of Momentum

 Impulse

Try to make a baseball and a cannon ball roll at the same speed. As you can guess, it is harder to get the cannon ball going. If you apply a constant force F for a time t, the change in velocity is given by Equatio. So, to get the same v, the product Ft must be greater the greater the mass m you are trying to accelerate.
To throw a cannon ball from rest and give it the same final velocity as a baseball (also starting from rest), we must push either harder or longer. What counts is the product Ft. This product Ft is the natural measure of how hard and how long we push to change a motion. It is called the impulse of the force.

Momentum

Suppose we apply the same impulse to a baseball and a cannon ball, both initially at rest. Since the initial value of the quantity mv is zero in each case, and since equal impulses are applied, the final values mv will be equal for the baseball and the cannon ball. Yet, because the mass of the cannon ball is much greater than the mass of the baseball, the velocity of the cannon ball will be much less than the velocity of the baseball. The product mv, then, is quite a different measure of the motion than simply v alone. We call it the momentum p of the body, and measure it in kilogram-meters per second