Finding PE given mass, distance, and energy lost.

1. Jan 6, 2015

Adam Affagal

1. The problem statement, all variables and given/known data
I'm supposed to find the potential energy at the start of a system for a vehicle given that the mass is 4000kg, the total distance traveled is 800m, and 3/4 of the total energy is lost to heat and friction by the end of the distance traveled (it's assumed that the vehicle starts from rest). Now, I know I can easily solve for a variable, but given this information I'm under the impression that I need to get a numerical answer. It's frustrating because I feel like I am not taking something into account.

2. Relevant equations
PE = mgh

3. The attempt at a solution
I've come up with really just substitution for the variables, so:
PE = 4500kg*9.8m/s^2*h.

2. Jan 6, 2015

jbriggs444

Is that all of the information that you have been given? It's not enough.

3. Jan 6, 2015

Adam Affagal

Unfortunately, yes. I have scoured over my worksheet - nothing. I've since emailed my professor, but any further input you guys have would be appreciated.

4. Jan 6, 2015

jbriggs444

You could try finding a formula for potential energy in terms of some other variable. For instance, as a function of speed at the end of the run.

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