Calculation of actual power of automobile engine Xiao Ming helped his father unload 500 N of unusual goods placed in the trunk of the car to reduce the load of the car. Assuming that the car runs at a constant speed of 72 km / h in a straight line, the resistance of the car before and after the load change is 2000 N and 1950 n respectively, how much w of the actual power of the car engine has been reduced (the answer is 1000 W,

Calculation of actual power of automobile engine Xiao Ming helped his father unload 500 N of unusual goods placed in the trunk of the car to reduce the load of the car. Assuming that the car runs at a constant speed of 72 km / h in a straight line, the resistance of the car before and after the load change is 2000 N and 1950 n respectively, how much w of the actual power of the car engine has been reduced (the answer is 1000 W,

V=72km/h=20m/s
△F=2000-1950=50N
Here, delta f is the driving force difference between the front and back
△P=△Fv=50*20=1000W
This is the solution of junior high school
There are too many factors to be considered

A car is moving in a straight line at a speed of 36 km / h, and the power of the engine is known to be 60 kW? (2) How much resistance does the car suffer?

(1) Automobile engine work w = Pt = 60000w × 600s = 3.6 × 107j; (2) automobile moving distance S = VT = 10m / s × 600s = 6000m; therefore, friction f = f = 3.6 × 107j6000m = 6000N. Answer: (1) automobile engine work 3.6 × 107j in 10 minutes; (2) the resistance of this automobile is 6000N