How do you calculate the pressure of a mass plus force? E.g. there is a stone of 1 kg on it somewhere. There is a force of 60 N on the stone. How much force or pressure is this together? Mass + force or mass x force?

Answer

What is certainly not possible is that pressure would equal mass + force. After all, you cannot add two quantities that have different physical units, just as you cannot add 5 meters to 3 kilograms.

A pressure is a force per area:

P = F / A

where that pressure is expressed in pascals.
So 1 pascal is 1 newton per square meter

So if you have a stone of 6 kg, with a base of let’s say 25 cm²then the pressure can be obtained as follows:

– the force with which the stone pushes on the base is gravity, so near the earth’s surface this is F = mg = 6 * 9.81 Newton = 58.86 Newton
– the surface is 25 cm²so 0.0025 m². (convert to meters!!)

=> the pressure = 58.86 / 0.0025 = 23 544 pascal.

This seems like a very large number, but a pascal is very small. Actually, this is because 1 Newton is also small, and it is divided over a square meter to get 1 pascal. Don’t forget that the air pressure is also close to 1013 hectopascals, so also a big number, which is 101300 pascals. In technological areas such as strengths, pressures in gigapascals are not uncommon.
Pressure is also expressed in bar, where 1 bar equals 100 000 pascals