Question

13.4. Young's modulus for iron is 1.9 x 10' Pa. When an iron wire 1.0 m long with a cross-sectional area of 4.0 mm
supports a 100 kg load, the wire stretches by
(

​

Answer 1

Answer:

0.0129 m

Explanation:

ΔL = FL / (EA)

where ΔL is the deflection,

F is the force,

L is the initial length,

E is Young's modulus,

and A is the cross sectional area.

F = mg = 100 kg × 9.8 m/s² = 9800 N

A = 4.0 mm² × (1 m / 1000 mm)² = 4×10⁻⁶ m²

ΔL = (9800 N) (1.0 m) / ((1.9×10¹¹ Pa) (4×10⁻⁶ m²))

ΔL = 0.0129 m