Question

Find the force required to permanently deform (stretch such that it snaps back to >0.2% longer than original length) a .04 m diameter bar if YS = 1000 MPa.

Answer 1

http://en.wikipedia.org/wiki/Tensile_strength

force/area=1000M N/m^2

Put in the area, and solve for force in N.

Answer 2

Yield Strength times area.

1000e6 x pi(.02m)squared = answer in newtons

about 1.26e6 newtons