Respuesta :
Answer:
Efficiency of the engine equals 20%
Explanation:
We know that when the car moves it must do work against the resisting forces to keep moving and this work is spend as energy by the engine to keep the car moving.
we know that
[tex]Work=Force\times Displacement[/tex]
Thus to keep the car moving for 100,000 meters the theoretical work that requires to be done equals
[tex]Work=560N\times 100,000m=56\times 10^{6}Joules[/tex]
Now the actual energy spend by the car equals the energy spend by burning 2.8 gallons of gasoline.
Thus the energy produced by burning 2.8 gallons of gasoline equals
[tex]2.8\times 100\times 10^{6}=280\times 10^{6}Joules[/tex]
Thus the efficiency is calculated as
[tex]\eta =\frac{56\times 10^{6}}{280\times 10^{6}}\times 100\\\\\therefore \eta =20percent[/tex]
