# Homework Help: Vertical Deflection Off Free End Of Bar

1. Nov 12, 2012

### ggl3

1. The problem statement, all variables and given/known data

The drawing shows a 152-kg crate hanging from the end of a steel bar. The length of the bar is 0.09 m, and its cross-sectional area is 3.80x10^-4 m^2. Neglect the weight of the bar itself.

(a) Determine the shear stress on the bar.
(b) Determine the vertical deflection ΔY of the right end of the bar.

2. Relevant equations
Stress=F/A
Tension=F=ma

Not quite sure what to do with deflection. I found ΔY=(F/A)(L/G) off another posts. Correct to use in this case?

3. The attempt at a solution

(a) This was pretty simple. Just found tension which was (152kg)(9.8). Then divided that by (3.8x10^-4). I got 3920000 N/m^2

(b) This is where I am having trouble. I used the equation off another problem.
This gave me ΔY=(3920000N/m^2)(.09m/(2.0x10^11)).
I found 2.0x10^11 by looking around for Young's Modulus of steel. This gave me an answer of 1.764x10^-6. However, the answer was marked wrong.