Question

An amusement park ride consists of airplane shaped cars attached to steel rods. Each rod has a length of 20.0 m and a cross-sectional area of 8.00 $c{m}^2$. Young's modulus for steel is $2\times {10}^{11}N/m^2.$
a. How much is the rod stretched (in mm) when the ride is at rest 2 (Assume that each car plus two people seated in it has a total weight of 2000 N.)

• A. 0.45 mm
  
• B. 0.25 mm
  
• C. 0.35 mm
  
• D. 0.55 mm
  

Answer 1

The correct option is B 0.25 mm

0.25 mm
Sln :
On substituting the values, we get
$\Delta l=\frac{F{l}_0}{YA}=2.5\times {10}^{-4}m=0.25mm.$