Solve Pressure Problem: Upward Force for Ocean Hatch

  • Thread starter Thread starter tommyhakinen
  • Start date Start date
  • Tags Tags
    Pressure
AI Thread Summary
To determine the upward force required to open a hatch of area 0.75 m² at a depth of 30 meters in the ocean, the internal pressure of 1 atmosphere must be considered alongside the pressure exerted by the water. The relevant equation combines atmospheric pressure and hydrostatic pressure: P = Patm + ρgh. The upward force can then be calculated using F = P*A, where P is the total pressure acting on the hatch. The approach discussed in the thread is correct for solving the problem.
tommyhakinen
Messages
34
Reaction score
0

Homework Statement


A submersible with internal pressure of 1 atmosphere is at a depth of 30 meter below the surface of the ocean. At this depth, what is the upward force required to open a hatch of area 0.75 m2. Assume density of sea water is 1030 kg/m3.

Homework Equations


P = Patm + ρgh
F = P*A

The Attempt at a Solution


Do I have to add the atmospheric pressure on the surface of the ocean? I have this equation : Patm + ρgh = Pinternal + P2
then F = P2 * A.
is this approach right?
 
Physics news on Phys.org
tommyhakinen said:
is this approach right?

Yes, looks good.

p.s. Welcome to PF.
 
Thank you..
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...

Similar threads

Back
Top