Posted by Nik on .
A fire hose exerts a force on the person holding it. This is because the water accelerates as it goes from the hose through the nozzle. How much force is required to hold a 7.5 cm diameter hose delivering 450 L/min through a 0.80cm diameter nozzle?

physics  fluids 
bobpursley,
The velocity will be increased as the inverse ratio of areas:
New velocity/oldvelocity=(7.5/.8)^2
The old velocity can be solved by
450L/min*1dm^3/L * 1min/60sec is flow in dm^3/sec, so divide that by area and you get linear flow.
acceleration=changevelocity/time so on a per second basis,
acceleartion=newvelocityoldvelocity
=oldvelocity((7.5/.8)^21)
and then, Force=mass/second*acceleration
= density*450L/60sec*acceleratin
check my thinking.