a 3200-lb car (Cd = 0.35, Af = 25ft^2, and p= 0.002378 slugs/ft^3) has 14-inch-radius wheels, a drivetrain efficiency of 93%, an overall gear reducation ratio of 3.2 to 1, and drive axle slippage of 3.5%. the engine develops a maximum torque of 210ft-lb at 3600 rev/min. what is the maximum grade this vehicle could ascend, on a paved surface, while the engine is developing maximum torque? (assume that the available tractive effort is the engine-generated tractive effort.)