The position of a particle along a straight-line path is defined by s=(t3−6t2−15t+7) ft, where t is in seconds. part a part complete determine the total distance traveled when t = 11 s . express your answer to three significant figures and include the appropriate units. st = 640 ft previous answers correct part b what are the particle's average velocity at the time given in part a? express your answer to three significant figures and include the appropriate units.