Problem: Suppose that the rate of flow of water through a fire hose is 21.4 kg/s and the stream of water from the hose moves at 14.9 m/s. What force is exerted by such a stream

Given Information:

mass flow rate = 21.4 kg/s

change in velocity = 14.9 m/s

Required Information:

Force = ?

Force = 318.86 N

Explanation:

We know that force is equal to change in momentum over time

F = Δp/t

Where change in momentum is

Δp = m(v₂² - v₁²)

so force becomes

F = m(v₂² - v₁²)/t

Where m/t is basically mass flow rate 21.4 kg/s

F = 21.4 kg/s*(v₂² - v₁²)

The change in velocity is given as

v₂² - v₁² = 14.9 m/s

F = 21.4 kg/s * 14.9 m/s

F = 318.86 kg.m/s²

1 kg.m/s² is equivalent to 1 Newton of force

F = 318.86 N

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

grav forces affect all objects magnetic forces affect magnetic objects and electric currents