Question

Find the weight required to stretch a steel road by 2 mm, if the length of the road is 2 m and diameter 4 mm. Y= 200 GPa and g -9.8 ms2? (a) 356.4 kg (b) 295.4 kg (c) 365.4 kg (d) 256.4 kg 3.

Answer 1

Answer:

Option D is the correct answer.

Explanation:

We equation for elongation

   $\Delta L=\frac{PL}{AE}$      

Here we need to find weight required,

We need to stretch a steel road by 2 mm, that is ΔL = 2mm = 0.002 m

$A=\frac{\pi d^2}{4}=\frac{\pi ({4\times 10^{-3}})^2}{4}=1.26\times 10^{-5}m^2$

E = 200GPa = 2 x 10¹¹ N/m²

L=2m

Substituting

$0.002=\frac{P\times 2}{1.26\times 10^{-5}\times 2\times 10^{11}}\\\\P=2520N=256.4kg$

Option D is the correct answer.