Momentum

In class this week, we have been talking about momentum. Momentum is the quantity of motion of a moving body. Momentum is equal to mass times velocity, and can be expressed in the equation, P(momentum)=M(mass) x V(velocity). This means that objects with more mass and more velocity have more momentum. Another thing we have been talking about in class is Impulse, which is equal to change in momentum. In the picture below there is a key and a pencil. Assuming someone threw both at you at the same velocity, the key would hurt more because it has more mass, which means more momentum.

If the key weighs .5kg, and the pencil weighs .2kg, and both are thrown at a velocity of 2m/s, we can calculate the momentum of both objects.

P_key=M_keyV_key

P_key=(.5kg)(2m/s)

P_key=1kg m/s

P_pen=M_penV_pen

P_pen=(.2kg)(2m/s)

P_pen=0.4kg m/s

The key has a momentum of .6kg m/s greater than the pencil.