A dental assistant can apply by means of a lever a force of

A dental assistant can apply by means of a lever a force of 30-lb to the piston of the dentist’s chair which has a patient in it. The force moves a small piston whose cross section is 2 in². If the cross section of the large piston which supports the chair and the patient is 20 in². (a) Find the pressure of the small piston against the fluid. (b) Find the pressure of the fluid against the large piston. (c) Find the maximum total weight the larger piston can withstand against the chair and the patient.  

Solution

a)

pressure = F/A = 30 / 2 = 15 lb/in²

b) according to pascal\'s law pressure applied to a point in a closed container is transmitted equally in all direction of that container

therefore pressure in large piston = 15  lb/in²

c) total weight the larger piston can withstand = force on larger piston = 15 x20 =300 lb