Question

The fluid transmission of a 30000-lb truck allows the engine to deliver constant power to the rear wheels.

Determine the distance required for the truck traveling on a level road to increase its speed from 40 ft/s to 70 ft/s if 95 hp is delivered to the rear wheels. Neglect drag and rolling resistance.

Express your answer with the appropriate units.

Answer 1

Initial speed of the truck, u 40ft/s Final speed of the truck, 70ft/s Power delivered, P -95 hp 52250ft Ibf /s Mass of the truck, 30000 32.2 931.68 1b Acceleration of the truck can be expressed as dv dls Applying Newton's law; force acting is given by, dv dls Power delivered is given by,

civ ds dv ds 52250-931.68xv2_ ds Rearranging,

2dv 52250 ds 931.68 = 56.08 56-08as =v'dv Integrating 56.08dsvdv V 170 56.08 xs =-140 (70,40%) 93000 Thus the required distance, -93000 56.08 1658.34 ft