# Please kindly help! (1 Viewer)

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#### bukky

Hi,
I just joined today and would like help with a question. Here it is:

It is a sunny day and you are lying on a beach . Some distance away across level gropund, is a tall coconut palm. As you watch, a monkey in that tree drops a coconut(from rest) onto hard ground below. The time elapsed from the moment he releases the coconut until it hits the pavement is 190% longer than the time it takes for the impact to reach you. The angle (measured with respect to the ground ) at which you are viewing the monkey when he drops the nut is 5 degrees. Assumimg the speed of sound is constant 343m/s, from what height did the monkey drop the nut?
Thanks

#### Chi Meson

Homework Helper
time for sound to reach you = (1.90t + t) =2.90t
time for coconut to fall = t
height of tree = y
distance from tree = x = y/(tan 5)

#### HallsofIvy

bukky, if this is homework or course work you should show us what you have tried on this. (If it isn't, this is the wrong forum.)

Chi Meson, did you misread the question? Bukky said ". The time elapsed from the moment he releases the coconut until it hits the pavement is 190% longer than the time it takes for the impact to reach you." (I presume the "impact" is the sound of the coconut hitting the pavement.) You say "time for sound to reach you = (1.90t + t) =2.90t". If t is the time it takes for the coconut to hit the ground, then the time for the sound to reach you is t/1.90.
Letting x be the horizontal distance to the bottom of the tree (where the coconut hits) then x= 343t/1.9= 180.5t. Letting y be the height of the tree, then y= 4.9t2. You can solve
tan(5)= y/x= (4.9/180.5)t= 0.027t for t and then find y.

#### bukky

HallsofIvy said:
bukky, if this is homework or course work you should show us what you have tried on this. (If it isn't, this is the wrong forum.)

Chi Meson, did you misread the question? Bukky said ". The time elapsed from the moment he releases the coconut until it hits the pavement is 190% longer than the time it takes for the impact to reach you." (I presume the "impact" is the sound of the coconut hitting the pavement.) You say "time for sound to reach you = (1.90t + t) =2.90t". If t is the time it takes for the coconut to hit the ground, then the time for the sound to reach you is t/1.90.
Letting x be the horizontal distance to the bottom of the tree (where the coconut hits) then x= 343t/1.9= 180.5t. Letting y be the height of the tree, then y= 4.9t2. You can solve
tan(5)= y/x= (4.9/180.5)t= 0.027t for t and then find y.
It is an assignment and we were( class) given any hunts on how to solve the problem.
I have attempted the problem numerous times. I was using the formula
v1-vo=2ax. I do have a question? how did you obtain 4.9t? is there a formula I could use to approach such a question in the future? I want to make sure I understand it. Rather than just obtaining the answer.

#### bukky

Chi Meson said:
time for sound to reach you = (1.90t + t) =2.90t
time for coconut to fall = t
height of tree = y
distance from tree = x = y/(tan 5)

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