# Homework Help: Superhero punching through a wall, breaking point of steel

1. Nov 4, 2011

### sbennett3348

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

Comic-book superheroes are sometimes able to punch holes through steel walls.
(a) If the ultimate shear strength of steel is taken to be 2.60X10^9 Pa, what force is required to punch through a steel plate 1.60 cm thick? Assume the superhero's fist has cross-sectional area of 104 cm2 and is approximately circular.

2. Relevant equations
P=F/A
Possibly F/A=Y*DeltaL/Linitial

3. The attempt at a solution

My attempt was P=F/A 2.6x10^9*(pi.104^2)=88346611.86

My teacher began doing the problem but got lost and was unsure how to proceed...she said she would have to look into it She gave us the answer which was 10500000N. I got lost with what she was doing and tried my own attempt. Meanwhile, our homework with an identical problem with different numbers is due before our next class. I am completely lost on how to do this problem. I would greatly appreciate help.