Posted by **suzanne** on Thursday, February 28, 2013 at 1:45am.

a soccer player kicks a rock horizontally off a 40.0-m-high cliff into a pool of water. if the player hears the sound of the splash 3.00 s later, what was the initial speed given to the rock? assume the speed of sound in air to be 343m/s.

- physics -
**drwls**, Thursday, February 28, 2013 at 2:32am
Neglecting air friction, the time it will take the rock to hit the water is

sqrt(2H/g) = 2.857 seconds. That means the sound of the splash takes 3 - 2.857 = 0.143 seconds to be heard, after hitting water. Sound travelled 49.05 m in that time. Since the cliff is 40 m high, the horizontal distance travelled by the rock was (from the Pythagorean theorem)

sqrt[(49.05)^2 -(40)^2] = 28.4 m

The rock's initial speed (and constant horizontal speed) was 28.4 m/2.857 s = 9.84 m/s

- physics -
**warnu**, Wednesday, December 24, 2014 at 11:17pm
9.84 m/s

## Answer this Question

## Related Questions

- physics - A soccer player kicks a rock horizontally off a 40.0 m high cliff into...
- physics - A soccer player kicks a rock horizontally off a 41.7 m high cliff into...
- physics - A soccer player kicks a rock horizontally off a cliff 42.9 m high into...
- physic - Question Part Points Submissions Used A soccer player kicks a rock ...
- Physics - A soccer player kicks a rock horizontally off the a 40 m high cliff ...
- pyhsics - A man drops a rock off the side of a cliff, and hears it hit the ...
- Physics - A soccer player kicks a rock with an initial velocity of 0.50 m/s from...
- physics - To estimate how high the cliff is you throw a rock off the edge and 7....
- physics - Soccer player #1 is 7.31 m from the goal, as the figure shows. If she ...
- physics - Soccer player #1 is 7.31 m from the goal, as the figure shows. If she ...

More Related Questions