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Fluids -- bringing together pressure, depth and friction
Hi Again!
More troubles with fluids.
I was pretty sure I had this one.
There is a
freshwater pond
density, D=1000 kg/m^3
depth = 15.1 m
one of the sides is blocked off by a cliff.
A nearly horizontal tube
diameter = 3.17 cm
depth below the pond's surface is 6.2 m
eroded to the other side of the cliff
a rock blocks cuts off the flow of the water.
The question asks for the frictional force between the tube's wall and the rock blocking the exit.
I figured it would be fairly easy, since
F = P*A
and we can find out the hydrostatic pressure.
so
P = Patm + D*g*h
P = 101300 + 1000*9.8*6.2
P = 162060 Pa
A = pi*r^2 = pi* (0.01585)^2 = 7.89e-4 m^2
and therefore,
F = P*A = 127.9 N is the force on the rock blocking the exit
because there is no acceleration, the system is at equilibrium
so Fnet = F(ontherock) - F(friction) = 0
so F(on the rock) = F(friction)
so then my answer would be 127.9 N
Could you point out where I've made an error, and push me in the right direction?
Hi Again!
More troubles with fluids.
I was pretty sure I had this one.
There is a
freshwater pond
density, D=1000 kg/m^3
depth = 15.1 m
one of the sides is blocked off by a cliff.
A nearly horizontal tube
diameter = 3.17 cm
depth below the pond's surface is 6.2 m
eroded to the other side of the cliff
a rock blocks cuts off the flow of the water.
The question asks for the frictional force between the tube's wall and the rock blocking the exit.
I figured it would be fairly easy, since
F = P*A
and we can find out the hydrostatic pressure.
so
P = Patm + D*g*h
P = 101300 + 1000*9.8*6.2
P = 162060 Pa
A = pi*r^2 = pi* (0.01585)^2 = 7.89e-4 m^2
and therefore,
F = P*A = 127.9 N is the force on the rock blocking the exit
because there is no acceleration, the system is at equilibrium
so Fnet = F(ontherock) - F(friction) = 0
so F(on the rock) = F(friction)
so then my answer would be 127.9 N
Could you point out where I've made an error, and push me in the right direction?