Momentum


When watching football, you probably have noticed that a bigger player is harder to stop than a smaller player running at the same speed. Sir Newton would have said that the bigger man has more "motion", which is defined as "momentum" today. This quantity of motion is measured by finding the product of the mass of an object and its velocity, that is:

Mass * velocity = momentum, or
mv=p (where p stands for momentum).

Since velocity is a vector quantity, and mass is a scalar quantity, momentum must be a vector quantity, with its direction the same as the velocity's direction.
The unit for momentum is kg*m/s. Using the above equation, we can see that a heavier player will have more momentum than a lighter player running at the same speed, and a faster player will have more momentum than a slower player with the same mass.

Newton's Second Law in Terms of Momentum

We have learned that according to Newton's second law, F=ma.

F=m(v-v0)/t

F=(mv-m0)/t

F=p-p0/t

F=Dp/t