An experimental rocket sled weighs 5200 lb and is propelled by six rocket motors each wi...

An experimental rocket sled weighs 5200 lb and is propelled by six rocket motors each with an impulse rating of 8600 lb-sec. The rockets are fired at 1-sec intervals, and the duration of each rocket firing is 2 sec. If the velocity of the sled 10 sec from the start is 200 mi/hr, determine the time average R of the total aerodynamic and mechanical resistance to motion. Neglect the loss of mass due to exhausted fuel compared with the mass of the sled.