A steam of water flowing horizontally with a speed of 15 ms-1 gushes o

1.	A steam of water flowing horizontally with a speed of 15 ms-1 gushes out of a tube of cross-sectional area 10-2 m2, and hits at a vertical wall nearby. What is the force exerted on the wall by the impact of water, assuming it does not rebound?
Answer» Volume of water striking the wall per second = v x A = 15 x 10^-2 = 0.15 m^-3 s^-1 Mass of water hitting wall per second = 9 x v x A = 1000 x 0.15 kg s^-1 = 150 kg s^-1 Initial momentum of water per second = 150 x 150 = 2250 kg ms^-1 Final momentum of water per second = 0 (There is no rebound of water) Magnitude of force = Rate of change of momentum = 2250 N

A steam of water flowing horizontally with a speed of 15 ms-1 gushes out of a tube of cross-sectional area 10-2 m2, and hits at a vertical wall nearby. What is the force exerted on the wall by the impact of water, assuming it does not rebound?

Answer»

Volume of water striking the wall per second = v x A

= 15 x 10^-2 = 0.15 m^-3 s^-1

Mass of water hitting wall per second

= 9 x v x A

= 1000 x 0.15 kg s^-1 = 150 kg s^-1

Initial momentum of water per second

= 150 x 150 = 2250 kg ms^-1

Final momentum of water per second = 0 (There is no rebound of water)

Magnitude of force = Rate of change of momentum

= 2250 N