Homework SourseA ball is thrown upward at 90ftsec from the top story buildi
A ball is thrown upward at 90ft./sec. from the top story building (60 feet high). How long will it take before the ball lands on the sidewalk below? please show your work step by step. thank you
Solution
a(t) = -32
v(t) = Integral [ a(t) ] dt = -32t + C
v(0) = 90 => C = 90
v(t) = -32t + 90
h(t) = Integral [ v(t) ] dt = -16t^2 + 90t + C
h(0) = 60 => C = 60
h(t) = -16t^2 + 90t + 60
h(t) = 0
-16t^2 + 90t + 60 = 0
-8t^2 + 45t + 30 = 0
Use the quadratic formula to find t:
t 6.227
