BR Physics Effect of density on hydraulic lift

[fluff]

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P. 95 in fluids and solids section.

Increasing the density of the hydraulic fluid would have what overall effect?

A. P1 and P2 would increase
B. P1 would increase; P2 would remain the same.
C. P2 would increase; P1 would remain the same.
D. P1 and P2 would be unaffected.

Why is the answer D? If density, p = M/V, increases, means that either mass increases or volume decreases. If mass increases, then will affect the force variable in the pressure equation, P = F/A. Doesn’t this mean that the pressure will increase?

 

[IntelInside]

P. 95 in fluids and solids section.

Increasing the density of the hydraulic fluid would have what overall effect?

A. P1 and P2 would increase
B. P1 would increase; P2 would remain the same.
C. P2 would increase; P1 would remain the same.
D. P1 and P2 would be unaffected.

Why is the answer D? If density, p = M/V, increases, means that either mass increases or volume decreases. If mass increases, then will affect the force variable in the pressure equation, P = F/A. Doesn’t this mean that the pressure will increase?

No it doesnt mean that F will increase. The force is what we apply to the hydraulic lift. It is independent of the density of the fluid. And Area will be constant

 

[fluff]

No it doesnt mean that F will increase. The force is what we apply to the hydraulic lift. It is independent of the density of the fluid. And Area will be constant

But then increasing density is sort of like increasing viscosity (increasing the # of particles in solution), so you would need a greater force to push down on the hydraulic lift??

 

[loveoforganic]

I don't believe viscosity and density necessarily covary.

 

[Vanguard23]

I don't have it in front of me, but I think you need to read what P1 and P2 ARE. They're not the pressure OF the fluid. They're the pressure *applied* to the fluid. And they are, naturally the same given F1/A1 = F2/A2. So if viscosity would not affect one(and it wouldn't given it's the pressure from the applied force on the lift) it wouldn't affect the other.

in other words, it's not asking for the pressure from rho*g*h.

 

[BerkReviewTeach]

I don't have it in front of me, but I think you need to read what P1 and P2 ARE. They're not the pressure OF the fluid. They're the pressure *applied* to the fluid. And they are, naturally the same given F1/A1 = F2/A2. So if viscosity would not affect one(and it wouldn't given it's the pressure from the applied force on the lift) it wouldn't affect the other.

in other words, it's not asking for the pressure from rho*g*h.

GREAT answer Vanguard.