Question

The world's total petroleum reserve is estimated at 2.0 x 10^22 joules La joule (J) is the unit of energy where 1J =1kg m^2/s^2). At the present rate of consumption, 1.8 x 10^20 joules per year (J/yr), how long would it take to exhaust the supply?

Answer 1

Answer:

It will take $1.1\times 10^{2}years$ to exhaust the supply

Explanation:

We have to apply unitary method to solve this problem.

Divide total petroleum reserve by petroleum consumption in each year to calculate estimated time.

Presently, $1.8\times 10^{20}$ joules of petroleum are being consumed per year.

Hence, applying unitary method, $2.0\times 10^{22}$ joules of petroleum can be consumed in $\frac{2.0\times 10^{22}}{1.8\times 10^{20}}years=1.1\times 10^{2}years$