a body moves on a coordinate line such that it has a position s=f(t)=t^2-8t+7 on the interval 0(greater than or equal to)t(greater than or equal to)9 with s in meters and t in seconds
a)find the bodys displacement and average velocity for the given time interval
b)find the bodys speed and acceleration at the endpoints of the interval
c)when,if ever,during the interval does the body change direction?
section 3.4
