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.

Question

Physics

Janetta

13 March, 09:40

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.

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Answers (2)

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Pamela Ballard · Answer 1

Refer to the diagram shown below.

The vertical distance traveled is

s = 25 m

The initial vertical launch velocity is zero.

Therefore

s = (1/2) * g*t²

where g = 9.8 m/s²

t = the time of flight, s

That is,

0.5*9.8*t² = 25

t² = 25/4.9 = 5.102

t = 2.26 s

Answer: 2.26 s

Kelsey Manning · Answer 2

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)