A boy standing on the top of a hill throws a stone horizontally with a velocity of 15 m/s. It hits level ground 23 m from the hill. How high is the hill? Assume that the acceleration due to gravity is 9.8 m/s2.

Question

A boy standing on the top of a hill throws a stone horizontally with a velocity of 15 m/s. It hits level ground 23 m from the hill. How high is the hill?  Assume that the acceleration due to gravity is 9.8 m/s2.

anonymous · Answer

Draw a picture and place the motion variables (X,Y,V,T,A) for the beginning and ending pictures ... place the origin (zero point)

then use 

$$Y_f = Y_i + V_{yi}t_f + 1/2A_yt_f^2$$