# A-level Physics (Advancing Physics)/Stress, Strain & Young's Modulus/Worked Solutions

1. stress=force/cross-sectional area

=100/(0.5x10^-6)m =200000000Pa

2. cross-sectional area=force / stress

=100N / 70MPa =1.428x10^-6

3. strain=extension/original length

=2/10 =0.2

4. Decimal --> percentage

0.2*100=20%

5. young modulus=stress/strain = (force/area)/(extension/length) = (force x length)/(area x extension) = (50 x 0.7)/(0.05 x (pi x 0.001^2) = 2.23x10^8

8. Tensile Strength = Force / Area = 0.95x10^6 = 25/A = 25 / 0.95x10^6 = A = A = 2.63x10^-5