Question

Assume a force of 30 N is distributed over a surface of area 2m^2 in such a way that at each point force can be considered to act at an angle of 30° to the normal at that point. What will be the value of pressure on that plane?

(a) 7.5 Pa

(b) 7.53–√ Pa

(c) 15 Pa

(d) 153–√ Pa

Answer 1

Right option is (b) 7.53–√ Pa

To explain I would say: One important thing to keep in mind is that pressure at a point is the normal component of force per unit area, NOT total force per unit area.

So, here we will take the normal component of 30N force, i.e:

30cos(30°)=153–√.

Press = F/A = 153–√/2

= 7.53–√ Pa.