If a stone is dropped into a lake from a tower, thesound of splash is heard by a man after 11.5 s, thenwhat is the height of tower?

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mvcdc | Student, Graduate | (Level 2) Associate Educator

Posted on

This problem involves a free-falling body, the rock. We know that it is dropped and so the initial velocity, `v_o` is `0`. The force of gravity is also acting upon the free-falling object, giving it a constant acceleration, the acceleration due to gravity, `g = 9.8 m/s^2.`

Assuming that there is no air resistance, we have the following formula for distance travelled, or the height from which the stone fell:

`h = v_o t + 1/2 g t^2`

Substituting what we know, we have:

`h = (0 * 11.5s) + 1/2 (9.8m/s^2)*(11.5s)^2`

`h = 0 + 1/2 (9.8 m/s^2) * (132.25s^2)` 

`h = 648.025 m`

Hence, the tower has a height of 648.025 meters.




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tinacullen-13 | Student, Undergraduate | (Level 1) Honors

Posted on

this is not the correct awnser,the time given is the total time for the stone to drop into water and the time it takes to reach our ears