# Trying to compare two different weights during drop through analysis.

1. Oct 14, 2014

### Spoolx

Hi guys,
I am working on a project at work where we make part a which weighs 10 pounds and part b which weighs 13 pounds.

Parts a and b both get packaged in a foam container. I have test data on part a that says it will survive drop tests, I was hoping to do analysis to say part b will also survive the drop test without actually having to test part b.
The drop height is 5 feet. The foam has a specification where it takes 90lbf to deflect it .25 inch

My initial calculation was to find the kinetic energy of both, and then divide by the displacement to find the force, however obviously the foam padding adds some sort of damping to the equation. So I really dont know how to solve this problem.
When I do my KE equation I can't figure out how to get rid of the ft from the numerator as I need lbs to calculate deflection of the foam.

Any help is greatly appreciated.

Thanks

Last edited: Oct 14, 2014
2. Oct 16, 2014

### elegysix

what is the condition for failure?

right off the bat, we can say part a does 5*10=50ftlb and part b does 5*13=65ftlb.
Is deflection greater than .25" the failure condition? If so, you can see that part b is < 90ftlb, and therefore ok.

does that help?