Question

A 2-cm-diameter vertical water jet is injected upward by a nozzle at a speed of 15 m/s. Determine the maximum weight of a flat plate that can be supported by this water jet at a height of 2 m from the nozzle. Take the density of water to be 1000 kg/m3 The maximum weight of a flat plate that can be supported by the water jet is____ N.

Answer 1

Answer:58.28 N

Explanation:

Given data

$dia. of nozzle \left ( d\right )=2 cm$

$initial velocity\left ( u\right )=15 m/s$

$height\left ( h\right )=2m$

Now velocity of jet at height of 2m

$v^2-u^2=2gh$

$v^2=15^2-2\left ( 9.81\right )\left ( 2\right )$

$v=\sqrt{185.76}=13.62 m/s$

$Now\ forces\ on\ plate\ are\ weight\left ( Downward\right ) and jet\ force\left ( upward\right )$

equating them

W=$\left ( \rho Av\right )v$

W=$10^{3}\times \frac{\pi}{4}\left ( 0.02\right )^2\times 13.62^2$

W=58.28 N