Physics Help Forum Fluid Statics

 Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

 Mar 20th 2016, 10:18 PM #1 Junior Member   Join Date: Mar 2016 Posts: 1 Fluid Statics I have a question from a text book it is, A Vertical freshwater lock is 5m wide and 3m high. The water level is 2.7m above the base of the lock on one side, there being no water on the other side. The mass of the lock is 4t and the coefficient of friction between the lock and the slides is 0.3. Determine the force necessary to raise the lock. So far i have done: Fw(lock)=4000*9.81=39,240 N Ff=Fn*0.3 Pressure=2.7*1000*9.81 = 26,487 Pa Area=5*2.7 =13.5m^2 Force=Pressure*Area =26,487*13.5 =357,574.5 N Im not too sure on what i am to do next and what Ff or Fn are im guessing the force required to move the lock would be Ff+Fw. Could you please show me how to get the answer
 Mar 29th 2016, 05:50 AM #2 Junior Member   Join Date: Feb 2016 Posts: 16 The pressure is not a constant, it changes linearly as you go deeper.. you need to calculate the equivalent pressure (pressure prism)

 Tags fluid, statics