Question

Joshni threw a ball and its height is represented by the function h(t) = -16t2 + 30t + 5. Explain how she can determine the maximum height the ball reached.

Answer 1

s = -16t² + 30t + 5

Now, v = ds/dt => -32t + 30 = 0....at maximum height

so, t = 30/32 => 15/16 seconds

Then, s = -16(15/16)² + 30(15/16) + 5

=> s = 19.0625 feet...the maximum height reached.

Answer 2

http://www.wolframalpha.com/input/?i=s+%3D+-16t%C2%B2+%2B+30t+%2B+5