Question

How long will the stone be in flight?

Answer 1

3 s

Explanation:

Using this quadratic, max height will occur at t = -b/2a

t = - 48 / (2*-16) = 1.5 seconds to max height

then another 1.5 seconds to fall to the ground

for a total of 3 seconds.

Another way d = 0 when it hits the ground

0 = -16 t^2 + 48 t + 0

0 = - 16t ( t +3 ) again shows t = 3s (or 0 before it is launched)