Do I use pi^2? How do I set up the problem I know it is F/A but I am at a loss.?

Question

Lost my notes on this section and want to make sure I did this problem correctly. pascal's principle, a hydraulic lift to raise a car weighing 1500N. The piston that supports the car has a diameter of 36 cm. What pressure of air within the system is required to just hold the car in place?

On Area do I use pi^2 to get the Area?

Answer 1

Pressure = Force / Area

You have the force and the area (which must be converted to square meters); compute the pressure.

Diameter = 36 cm so radius = .18 m and area = π( .18 m )²

Answer 2

If I understand your question correctly you are looking for the formula to calculate the surface area of the piston with a diameter of 36 cm. In that case the formula is A = Pi(r^2)

r = 36/2

thus the area is 1017.87601976 cm^2

Answer 3

P = F/A

P = (force acting on car due to gravity)/(area of piston that touches car)

P = (weight of car in Newtons)/(area of circle part of piston)

P = (1500 N)/(π(0.18 m)^2)

P = 1.5 x 10^4 Pa

P = 15 kPa