Question

If two forces in the ratio 5:7 act on two areas in the ratio 4:5, find the ratio of the pressure exerted.

Explain with complete calculations & justifications.

Answer 1

pressure=Force/area
P:p=
F/A:f/a
5/4:7/5
5/4*5/7
25/28
=25:28

Answer 2

we know,

pressure is the force act on per unit cross section area . e.g pressure = force/area

P1/P2 =F1.A2/F2.A1
=(F1/F2)(A2/A1)

given,

F1/F2 = 5:7
A1/A2 =4:5 so, A2/A1 =5:4

hence,
P1/P2 =(5/7)(5/4) =25/28

hence pressure ratio = 25 :28