Author Question: How much does it cost a household to run its coffee machine if it is used two hours per day and ... (Read 62 times)

CharlieWard · **on:** Jul 28, 2018

How much does it cost a household to run its coffee machine if it is used two hours per day and draws 1500 W? Assume the cost of electricity is 0.08/kWh.

What will be an ideal response?

Question 2

In addition to destroying the ozone layer, nitrous oxide from fertilizer contributes to global warming by emission of methane, a greenhouse gas.

What constraints can there be on Earth's population if we assume that about half the current population is (mostly) vegetarian? How does vegetarianism affect Earth's carrying capacity?

katara · **Reply #1 on:** Jul 28, 2018

Answer to Question 1

The coffee machine's energy use is 1200 W x 2 h = 2400 Wh = 2.4 kWh. At a
cost of 0.08/kWh, this comes to 2.4 kWh x 0.08/kWh = 0.19.

Answer to Question 2

It is possible to argue that growing crops is less disturbing to the environment
than raising animals for people to eat because grain is lower on the trophic pyramid.
However, as we see here, this can also cause problems for the environment.
Many more vegetarians can be sustained by Earth in any case than carnivores. This is a
more minor problem than living higher on the trophic pyramid.