Homework Help: Gravitational energy help !

1. Oct 7, 2012

layla2525

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

I am 65 kg and eat a 500 Calorie lunch and go hiking up a mountain afterwards. Assuming that chemical energy is converted to gravitational potential energy with 50% efficiency, approximately how many miles up the mountain can I go before I need my dinner?

0.5 miles

1 mile

2 miles

3 miles

4 miles

2. Relevant equations

3. The attempt at a solution

I solved for height by (2.0 x 10^(6))/ (65kg)(9.8)
which gave me 301538.4615, and then dived it by 2 because of the efficiency and got 1569.8587, now how can i convert into miles?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 7, 2012

layla2525

250-Calorie* snack, which contains 1x10^6 J

3. Oct 7, 2012

Andre

Close yes but 250 calories is not a lot. It's likely that kilo-calories is intended.
What is a relevant equation for potential energy (in units?)

Last edited: Oct 7, 2012
4. Oct 7, 2012

layla2525

I got 1569 for my efficiency What do I do after I get the Efficiency ?