Bill kicks a rock off the top of his apartment building. it strikes a window across the street 13 m away. the acceleration of gravity is 9.8 m/s 2 . if the window is 25 m below the position where bill contacted the rock, how long was it in the air? answer in units of s.

This problem fall under the "equations of motion" the formula to follow on this problem is "d=Vit + 1/2gt²". The initial Velocity of the rock will be Zero, Therefore Vi=0 Distance d=25m, g=9.8m/s². Since Vi=0 cancel it to the equation above. The equation will be d=1/2gt². Solve for time "t' the final equation will be t=√2d/g or t=√2(25m)/9.8m/s²= (ans in seconds)