# A biker traveling with a velocity of 80 feet per second leaves a 100 feet platform and is projected directly…

A biker traveling with a velocity of 80 feet per second leaves a 100 feet platform and is projected directly upward.  The function for the projectile motion  Is s(t) = -16t2 +80t + 100  where s(t) is the height and t is the seconds the biker is in the air.

a)      Looking at your calculator, find the number of seconds the biker is in the air (or â€œhang timeâ€).  Then find the range of height values that the biker attains.

b)      State the domain and range of this real life example.  Remember that time isnâ€™t negative and that the model is valid only when the biker is in the air!

c)      Use the graph to determine when the biker will reach a height of 100 feet.  State the (these) point(s) as an order pair and using functional notation.

d)     Use the graph to determine what height the biker will attain after 1 second.  State the point as an ordered pair and using functional notation.

Where is the function increasing?  In other words, for what x-values does the biker continue to get higher?  Where is the function decreasing? In other words, for what x-values does the biker start descending toward the ground?  State these intervals using interval notation