100
10,uus
11. a ball is thrown upward at a velocity of 15 meters per second from a height that is 20
meters above the ground. the height h (in meters) of the ball at time t in seconds) after it
is thrown can be found by h(t) = -5t^2 + 15t + 20. find the time when the ball is again 20
meters above the ground.
a
1 second
(b
2 seconds
c
3 seconds
d
4 seconds