OCR Physics A Forces, Fields and Energy January 2005 Q2

Bit stuck on this question. It's about the operation of an electrically-operated shower.

The water moves at a constant speed through a pipe of cress section 7.5 x 10^-5 m^2 to a shower head. The maximum mass of water which flows per second is 0.090 kg s^-1 We're also given the density of water as 1000 kg m^-3. At this point it asks us to show, for 2 marks, that the maximum speed of the water in the pipe is 1.2 m s^-1.

Now I've tried playing around with all sorts of equations and basically not got very far so if someone can at least give me at least some pointers or maybe even a solution that'd be great. It doesn't seem very 'routine' given that its quite early in the paper, or maybe I'm just making it more complicated than it really is lol. Anyway, any help would be gratefully received

Think of it as a cylinder of water passing a point per second, so cinsider a time difference of 1 second, in which case the mass of the cylinder of water is 0.090kg. That's the mass, you can use the density to figure out the volume. This is the volume of the cylinder, you have the area so you can calculate the length. This is the length of water that flows past a point per second, ie the speed.

haha, our class has done that question so many times and we never remember how to do it!! i gotta say, i think its the hardest question i've seen in all of the FFE papers! Do u want the mark scheme for it?
..:: Sim ::..

haha, our class has done that question so many times and we never remember how to do it!! i gotta say, i think its the hardest question i've seen in all of the FFE papers! Do u want the mark scheme for it?
..:: Sim ::..