Question

A ton of coal holds about 3.2E10 J of energy and costs about 40 dollars. How many mega joules of energy in the form of coal can you get for a dollar?

Answer 1

First you must calculate the amount of energy given by one dollar of coal:


`1\$\cdot (3.2\cdot 10^(10)\ J)/(40\$) = 8\cdot 10^8\ J`

In order to express the result in MJ (megajoules), I'm going to use a conversion factor:


`8\cdot 10^8\ J\cdot (1\ MJ)/(10^6\ J) = \bf 8\cdot 10^2\ MJ`