For a car with a mass of 2T, when driving on a straight road, the resistance is always 0.2 times of the gravity. After driving at a constant speed for 2km, the engine is turned off, and then it stops after driving for 55m. It is necessary to explain the work (g = 10N / kg) of the traction force on the car in the whole process

For a car with a mass of 2T, when driving on a straight road, the resistance is always 0.2 times of the gravity. After driving at a constant speed for 2km, the engine is turned off, and then it stops after driving for 55m. It is necessary to explain the work (g = 10N / kg) of the traction force on the car in the whole process

m=2t=2000kg
Resistance f = 0.2g = 0.2mg = 0.2 * 2000 * 10 = 4000N
When driving at a constant speed:
Traction f = resistance f = 4000N
The work done by traction on a car is
W=FS=4000N*2km=4000N*2000m=8*10^6J
After turning off the engine:
F = 0, no work done
In the whole process, the work done by the traction force on the car is 8 * 10 ^ 6J