Question

4. A metallic bar 50cm long has a uniform cross-sectional area of 4.0cm². If a tensile force of 35kN produces an extension of 0.25mm, calculate the value of Young's modulus.

Accepted Answer

Young's modulus, E = (F/A)/(e/L) = FL/(Ae)
F=35,000N, A=4.0×10⁻⁴m², L=0.5m, e=0.25×10⁻³m
E = (35,000×0.5)/(4.0×10⁻⁴×0.25×10⁻³)
E = 17,500/(1.0×10⁻⁷)
E = 1.75×10¹¹ Pa (N/m²)

WAEC Physics 2014 Theory — Question 4

Sign up free to unlock