Question

A 2650-lb car is traveling at sea level at a constant speed. its engine is running at 4500 rev/min and is producing 175 ft-lb of torque. it has a drivetrain efficiency of 90%, a drive axle slippage of 2%, 15- inch–radius wheels, and an overall gear reduction ratio of 3 to 1. if the car's frontal area is 21.5 ft 2 , what is its drag coefficient?

Answer 1

Check the attached file for the answer.

Answer 2

the drag coefficient is given by   
C =( (F - fW) * 2 ) / ( A*V*V*r)  
 V = speed of the vehicle = 192.42 
 f = cofficient of rolling resistance = 0.0231 
 F = traffic effort = 378 
 r = density of air = 0.002378 
 A = frontal area of the vehicle = 21.5 
W = weight of the vehicle = 2650 
 by substituting all the values in the above equation  
 drag coefficient = C = 0.167