1 answer
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constant a = -g = -9.81 m/s^2
v = Vi + a t
where Vi = 6.63 and a = -9.81
so
v = 6.63 - 9.81 t
h = Hi + Vi t + (1/2) a t^2
where Hi = 12.7
so
h = 12.7 + 6.63 t - 4.9 t^2
Now
at ground h = 0
so
4.9 t^2 - 6.63 t -12.7 = 0
t = -1.06 (before you threw it) and t = 2.42 seconds (use that)
v = 6.63 - 9.81 t = -17.1 m/s