# Homework Help: Elementary Physics - Energy Related Problem

1. Oct 20, 2011

### Valedictorian

1. The problem statement, all variables and given/known data
A worker on the roof of a building that is under construction dropped a 0.125 kg wrench over the edge. another workman on the 8th floor saw the wrench go by and determined that its speed at that level was 33.1 m/s. the first floor of the building is 12.0m high and each successive floor is 8.00m high. Neglecting air friction, how many floors does the building have? How fast was the wrench falling just before it hit the ground? What was its kinetic energy just before it hit the ground?

2. Relevant equations
PE=mgh
m-mass, g=9.8, h-height
KE=1/2 X mv^2
Ek-kinetic energy
PE = Potential Energy
KE = Kinetic Energy

3. The attempt at a solution
I don't really have any idea on how to solve this...it was a prize question by my teacher. Thanks in advance for any help!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 20, 2011

### LawrenceC

First thing to do is to determine how much higher the top of the roof is than the 8th floor where the other workman somehow determined the speed of the wrench.

Hint: How does potential energy relate to kinetic energy in this problem?

3. Oct 20, 2011

### Valedictorian

Nevermind, I just thought the problem was more intimidating than it really was. Thank you for your help though!