Question

David eats a basket of chocolates and cake that contains `20,000` calories of energy, then regrets it and thinks about how far up a mountain he will need to climb to work off this energy. Can you give him an answer?

Answer 1

`20,000` calories (not kilocalories) is `83,700` `J`

`E_p=mgh`, so `h=E_p/(mg)=83,700/(50xx9.8)=170` `m`

That's a little more than a staircase, a little less than a mountain.

I suspect the question meant kilocalories though, since 20,000 of those is more realistic for a basket of chocolate and cake. They are sometimes written as 'Calories' with a capital C.

If it meant kilocalories we need to multiply this answer by 1000, which would make it `170` `km`, which is much taller than any mountain on earth.