A 20-m long steel wire (cross-section 1.0 cm², Young's modulus 2.0 * 1011 N/m²), is subjected to a load of 25 000 N. How much will the wire stretch under the load?

Question

Quizplus · Accepted Answer

We can use the formula for the strain of a stretched wire:

strain = (applied force)/(cross-sectional area x Young's modulus x original length)

Plugging in the given values, we get:

strain = (25,000 N)/(1.0 cm^2 x 2.0 x 10^11 N/m^2 x 20 m) = 1.25 x 10^-7

The amount of stretch is then:

stretch = strain x original length = (1.25 x 10^-7) x 20 m = 2.5 x 10^-6 m = 2.5 cm

Therefore, the answer is (B) 2.5 cm.

A 20-M Long Steel Wire (Cross-Section 1