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Water drop velocity homework

  • Thread starter way2fasts
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Homework Statement


Water drips from the nozzle of a shower onto the floor 215 cm below. The drops fall at regular (equal) intervals of time, the first drop striking the floor at the instant the fourth drop begins to fall.

a) Find the location of the third drop as measured from the nozzle of the shower when the first drop strikes the floor. in cm below nozel

b) Find the location of the second drop as measured from the nozzle of the shower when the first drop strikes the floor.


Homework Equations





The Attempt at a Solution




Ok I am going to be honest never have posted here, but I am really confused about this problem, hopefully someone is able to explain this to me.

Well here is what I did, I thought that because there were 4 drops of water i would make t=3t.

then with the x(t)= Xo + 1/2(a)t^2 formula to find out the total time.
0=215+(1/2)(980)t^2
-215=-490t^2
-215/490=t^2
t=.662401

I thought that by getting the total time I would be able to just divide that by 3 to get just T alone so then I would only have to plug the time at that certain interval into a velocity equation. But the problem is when i do this my position is fairly high for 2 and 3, its about 215cm for 2, and 329 cm away from the nozel at 3. can anyone help to show me what I am doing wrong
 

Answers and Replies

  • #2
ehild
Homework Helper
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then with the x(t)= Xo + 1/2(a)t^2 formula to find out the total time.
0=215+(1/2)(980)t^2
-215=-490t^2
-215/490=t^2
t=.662401

I thought that by getting the total time I would be able to just divide that by 3 to get just T alone so then I would only have to plug the time at that certain interval into a velocity equation.
Although you handle the -signs in a random way, the result for the time is correct. It is also true that the drops follow each other at t/3 seconds.

But what do you mean on plugging into a velocity equation? You need the distance of the drops from the nozzle. The third drop had travelled for t/3 s when the fourth drop started, that is, when the first one hit the ground. What is its distance travelled?

ehild
 

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