physics help

Question

An arrow is fired horizontally from the top of a 50.0 m vertical cliff and lines 120 m away. At what speed was the arrow fired? Show your work please 

Answer 1

To do this you'll need to recognize that the vertical sub-problem will end at the same time as the horizontal sub-problem.  Setting the two equations equal to each other, solved for time, will let you determine the speed it takes to travel the 120 m in the horizontal sub-problem. The vertical sub-problem is only influenced by gravitational acceleration, no initial velocity; while the horizontal sub-problem is not influenced by any acceleration and has a constant velocity.  The time for this part could be expressed as d/v.