Answer to Question #125612 in Physics for lucy

Question #125612
Calculate the efficiency of the following devices:
A lawnmower which converts 143 J out of every 450 J of electrical input energy into sound and heat. The rest of the energy is converted to kinetic energy of the blades attached to the motor.
1
Expert's answer
2020-07-08T13:14:35-0400

The useful work done by the lawnmower is: 450J143J=307J450J-143J = 307J. By definition, the efficiency is the ration of the useful work and total input energy. Thus:


η=307J450J×100%68.2%\eta = \dfrac{307J}{450J}\times 100\% \approx 68.2\%

Answer. 68.2%


Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!

Leave a comment