# Throwing a dart from a roof - Velocity

by mybrohshi5
Tags: dart, roof, throwing, velocity
 P: 365 1. The problem statement, all variables and given/known data A dart is thrown horizontally from a buildings rooftop. The dart's time of flight is 2.0 s. The dart sticks in the ground such that it makes a 53.1 degree angle with the ground. With what speed was the dart thrown? 3. The attempt at a solution I am studying for my final and i do not get this problem from one of my previous tests. The answer is 14.7 m/s and i have no idea how to get it. Can anyone point me in the right direction. Thank you :)
 HW Helper P: 6,193 Well if it is throw horizontally, then the initial vertical velocity is zero right? Using an equation of motion, what would be final vertical velocity when t=2?
 P: 365 Is the final vertical velocity when t=2 just 19.6 m/s I got that from Vf = Vi + at oh so then from that the x component of the Vf will be the same as the velocity initial correct? so tan(53.1) = 19.6 / Vfx Vfx = 14.7 m/s Does that seem right?
HW Helper
P: 6,193

## Throwing a dart from a roof - Velocity

Yes that looks correct.
 P: 365 Yay! thank you very much :)

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