By tracing the figure, we see that we go around a semicricle twice and go in a straight path twice. So the perimeter of this figure consists of two semicircles and two line segments, hence the answer is C.
The maximum time 1.75 second in case of not having the height: 1. change in ax²+bx+c form⇆ -16t²+56t-40=h h=(8-8t)(2t-5) h=16t-40-16t²+40t h=-16t²+56t-40 2. t max=-b/(-2a)=-56/(-2×-16)=1.75 second
