Question

A flat plate is placed normal to a discharging jet of water. The jet discharges water at the rate of 0.2 $m^3$s${}^{-1}$ and at a speed of 18 ms${}^{-1}$. The force on the plate due to the jet, if the collision is inelastic is:

• A. $6N$
• B. $3N$
• C. $360N$
• D. $3600N$

Answer 1

Answer: (D)

$3600N$

Rate of discharge from jet $=0.2m^3/s$

Speed of water $=18m/s$

Force exerted by the jet on the plate $=\rho QV$

$=1000\times 0.2\times 18$ N

$=3600N$