How much pressure would one nail exert if an 80 kg person stepped on it? the radius of the nail is 0.5mm?

First, you need to find the force. This will be a gravitational force, so we will use F=mg, converting





F=mg


F=(80 kg)(9.81 m/s2)


F=784.8 N





Now, we can use the pressure formula. Pressure is defined as force over area, so we just need to find the area. If a person was to step on a nail, they would only feel pressure where the nail was, so the area will just be the area of the cross-section of the nail. Let's find its area (converting mm to m)





A=pi r^2


A=pi (0.5/1000)^2


A = 7.85e-7





Now we'll just plug everything into the pressure formula


P = F/A


P = 784.8/7.85e/7


P=9.99e8 Pa





And we'll probably want to convert this to something smaller. Megapascals (MPa) is the most common unit. There are 1000000 Pa to one MPa





9.99e8/1000000 = 999 MPa





Answer = 999 MPa