The function s = f(t) gives the position of a body moving on a coordinate line, with s in meters and t in seconds. s = 7t- th, Ost=7 Find the body's speed and acceleration at the end of the time interval. A 21 m/sec, -14 m/sec2 B 7 m/sec, - 2 m/sec2 -7 m/sec, - 2 m/sec2 7 m/sec, -14 m/sec2