Brain Teasers
Renewable Energy
For his science fair project, John decided to experiment with renewable energy sources. He hoped that his work will solve all of our energy problems. He decided to power a generator with an electric motor. He thought once the generator was up to speed, he could just flip a switch and the generator could supply the electricity that powered the electric motor. John was for sure he made a historical discovery, he found an alternative to fossil fuels. His energy source was purely renewable. Why did his experiment fail once he put it to the test?
Hint
If his invention works he will be breaking one of the most fundamental laws of science.Answer
Even if the generator and electric motor were 100% efficient, his set up would still not work. The maximum amount of electrical power that the generator can supply is equal to the mechanical power that the electric motor provides. So once the generator powers the electric motor, there would be no power left to run any additional electrical appliance. If it worked it would be breaking the Conservation of Energy Law; he would be making energy out of nothing. In reality, neither the motor nor the generator are 100% efficient. The generator doesn't convert all of the mechanical power to electricity and the motor doesn't convert all of the electrical power to mechanical power. A lot of the power is lost as heat. So in reality, besides not being able to power any additional appliances, the generator and motor would stop running after a short period.Hide Hint Show Hint Hide Answer Show Answer
What Next?
View a Similar Brain Teaser...
If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.
Solve a Puzzle
Comments
Good one. Got it though
I actually wanted to try this when I was a kind thinking it would work. Nice one
i already have a masters degree from MIT in boring, impossibly hard teasers that make me feel smarter that anyone else,so this was a piece of cake for me and everyone i know
hey good one! didnt get it but felt stupid as soon as i read the answer. maybe i should go back to school.
If the whole apparatus made audible sounds, it would also lose energy to that.
energy is neither created or destroyed but converted from one form to another..... I got it yay! but i cant explain it though
Thank you very much bro.I was going to do the same experiment but now I know that it wont wor.
To post a comment, please create an account and sign in.
Follow Braingle!