Your little brother is outside squirting a basketball with the stream of water from a garden hose. As the ball rolls across the yard, you begin to wonder what you would need to know in order to determine the rate at which momentum is transferred from the water to the ball. It should not be hard to measure both the radius \(r\) of the hose and the flow rate \(Q\) of water out of the hose in cubic meters per second. The density of water is certainly known, but you aren't sure whether the collision is elastic or inelastic.