Answer:
2.08secs
Explanation:
Given the equation modeled by the height as h=-121t^2 +504t
The velocity of the object at the max height is zero, hence;
v = dh/dt = 0
dh/dt = -2(121)t + 504
dh/dt = -242t + 504
0 = -242t + 504
242t = 504
t = 504/242
t = 2.08secs
Hence the projectile reaches its maximum height after 2.08secs