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A monkey falls from a tree problem

  • Thread starter gurpalc
  • Start date
  • #1
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Homework Statement



http://imgur.com/YEVAL

Homework Equations



x= x.initial + v.initial(t) + .5(a)t^2

v= v.initial + at

v^2= v.initial^2 + 2ad

The Attempt at a Solution


I tried plugging into above formulas but there were too many unknowns.
I'm not sure what I'm missing. Please help, I'm sure this is a simple question.
Also, only kinematics allowed, not potential energy.
 

Answers and Replies

  • #2
PhanthomJay
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The angle theta can be determined from the givens. Both the dart and monkey fall at the same rate downward. Better get the monkey before it hits the ground at what time?
 
  • #3
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The angle theta can be determined from the givens. Both the dart and monkey fall at the same rate downward. Better get the monkey before it hits the ground at what time?
I don't know how to get the time
 
  • #4
PhanthomJay
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How long does it take the monkey to hit the ground? Use one of the kinematic equations knowing the vertical distance and the downward acceleration of the monkey. You listed it already.
 
  • #5
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ok thanks
 
  • #6
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also what should my displacement be. should i use -10-0 or something to do with y. I am confused on that part
 
  • #7
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ok i got the time. but i don't know how to find vertical velocity because i don't know what to use for displacement of dart.
 
  • #8
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what do h and y have to do with the question
 
  • #9
1,065
10
There 3 motions here.
1. the dart travelling horizontally.
2. the dart travelling vertically
3. monkey travelled vertically.

It means the monkey and dart are at same location after travelling at same time when they meet.

Let the time=t
Let the point of meeting at coordinate x,y.
 
  • #10
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is the answer 33.725 m/s. I used -1.2 meters for displacement because the question wanted minimum velocity and that meant when the monkey hit the ground, the dart would hit him, right? And from the diagram, we see the gun is 1.2 meters above ground by 11.2-10. Is this right?
 
  • #11
1,065
10
There 3 motions here.
1. the dart travelling horizontally.
2. the dart travelling vertically
3. monkey travelled vertically.

It means the monkey and dart are at same location after travelling at same time when they meet.

Let the time=t
Let the point of meeting at coordinate x,y.
Write all the equations for 3 motions I've mentioned and we will check if they need any corrections.

Let the initial velocity = v, angle=θ
 
Last edited:

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