Answer:
58.32 N
Explanation:
Area of a circle = 

where r is the radius of the circle.
The cylinder has a radius of 0.02 m, its area is;
= 

=
x 
=
x 0.0004
= 1.2571 x 
Area of the cylinder is 0.0013
.
The safety valve has a radius of 0.0075 m, its area is;
= 

=
x 
=
x 5.625 x 
= 1.7679 x 
Area of the valve is 0.00018
.
From Hooke's law, the force on the safety valve can be determined by;
F = ke
= 950 x 0.0085
= 8.075 N
Minimum force,
, required can be determined by;
= 
= 
= 
= 58.32
The minimum force that must be exerted on the piston is 58.32 N.