A rock is thrown directly upward from the edge of a flat roof of a building that is 56.3 meters tall. The rock misses the building on its way down, and is observed to strike the ground 4.00 seconds after being thrown. Take the acceleration due to gravity to have magnitude and neglect any effects of air resistance. With what speed was the rock thrown?
Some people keep suggesting to use the equation:
y = yo + vot + 1/2at^2
set up like: 0 = 56.3 + vo(4) + 1/2(9.8)(4^2)
But that can't be right, because 4 seconds is the time it took from when it left the throwers hand to when it hit the ground. Not the time it took to travel 56.3 meters.
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A train 900'm long takes 1minute to cover a bridge of 300 m calculate its average speed
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