If the total momentum of a system of an old woman pushing a shopping cart is 450 kg×m/s, both with a velocity of 3 m/s, and the woman has a mass of 50 kg, what is the mass of the cart?

100kg

Explanation:

Momentum is defined as the product of mass times velocity:

The total momentum M must be equal to the sum of momentums of the system components, in this case the momentum of the lady plus the momentum of the cart:

since both the woman and the shopping cart have the same velocity:

the equation becomes:

and since we need the mass of the cart we solve for :

the values given by the problem are the following:

total momentum:

mass of the woman:

velocity:

we substitute all of them in the equation to find the mass of the shopping cart:

the mass of the cart is 100kg.

statement #3 on andre"s list is false.