Question

Problem 2 A 4,000 lb. vehicle (Cp = 0.45, AF = 33 ft?) is being driven on a paved surface at sea level (p = 0.002378 slugs/ft) at a speed of 70 mph. The available tractive force of the vehicle is 400 lb. The vehicle encounters a mountain (yes, the mountain is at sea level) with a very steep grade (G=0.08 ft/ft) that extends for precisely 2 of a mile before leveling out. Assuming the air density remains constant and the available tractive force of the vehicle is maintained at its maximum, what will the final speed of the vehicle be at the top of the mountain? Hint: First set up the sum of forces and get acceleration as a function of velocity. Then, noting that Vat V2 + 2 * a * Ad and Ad = VAt, you can get an equation that can be solved in discrete time intervals. Solve this using no more than 0.5 second intervals.

Answer 1

DELTA PO No I speed = 70 mph Surface at sea level; P = 0·002378 slugs / ft² CD = 0.45 As = 33ft² Steep grade G= 0.08 Ft / ft We have to find the final speed of the vehicle be at the top of the mountain V = 70 X 5280 st 3600 TV = 102.67 ft/s Reight Potential) p = P Cp AF V² 27550 = 0.002378 X 33 (0267) 1100 Hp = 18.72 hp)