Throwing a dart from a roof - Velocity

[mybrohshi5]

Homework Statement

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?

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 :)

 

[rock.freak667]

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?

 

[mybrohshi5]

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?

 

[rock.freak667]

Yes that looks correct.

 

[mybrohshi5]

Yay! thank you very much :)