Fluid Mechanics

Step 1: Find the volume of water hitting the wall each second.
The formula for flow rate (volume per second) is:
Volume per second = Area × Velocity
Here, Area =2×10−3m2 and Velocity =12ms−1
Volume per second =2×10−3×12=24×10−3m3∕s
Step 2: Find the mass of water hitting the wall each second.
To get the mass per second, multiply the volume flow by the density of water ( ρ=1000kg∕m3 ):
Mass per second = Density × Volume per second
=1000×24×10−3=24kg∕s
Step 3: Calculate the force on the wall.
Force is the change in momentum per second. The water hits the wall at velocity 12ms−1 and stops instantly.
Force = Mass per second × Velocity
=24×12=288N