Hi
h(t) = -9.8t^2 – 10t + 210, where t is in seconds, and height is in meters
when it hits the ground: h(t) = 0
-9.8t^2 – 10t + 210 = 0 |multiplying thru by -10
98t + 100t - 2100 = 0
49t^2 + 50t - 1050 = 0
|tossing out negative solution for time
t = 4.15 (rounded to the nearest hundredth's place)