(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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 3.00s later, what was the initial speed given to the rock? Assume the speed of sound in air to be 343 m/s.

2. Relevant equations

Well to start off I have a graph which I don't know how to put it in here. To get things started Im currently taking General Physics and it seems a bit confusing than I thought.

Teacher gave us this:

r= x= ro + Vox t

y= Yo + Voy t + (gt^2)/2

v= Vfx= Vox

Vfy= Voy + gt

Im not sure if theres more to this ^

To my understanding where r= displacement if im correct, and v is velocity(speed)

it seems that i plug in numbers and calculate them but im having problem understanding the letters what they represent so i can't get to my solution or explain that, thats my solution. It may sound confusing

3. The attempt at a solution

Height= 40m

a=g=9.8 m/s^2

speed of sound= 342m/s

Time=3s

r = r0 + Vot + (gt^2)/2

= 0 + 342 m/s *3.0s -4.9m/s^2 * 3.0s^2

= 984.9 m

so then I used:

x = x0 Voxt

984.9m = 0 + Vox * 3s

Vox= 328.3 m/s

and:

y= y0 + Voyt + (gt^2)/2

40m= 0 + Voy*3 + -4.9m/s^2 * 3.0s^2

Voy= -28m/s

and im stuck :( any help on what/how to get intial Velocity. Thanks in advance

Im new to forums as well :P

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Initial Velocity of a kicked rock

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