Find the tension in the wire and the components of the force exerted

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SUMMARY

The discussion focuses on calculating the tension in a wire and the components of the force exerted by a wall on a cantilever beam supporting a bear, a basket, and the beam itself. The bear weighs 720 N, the beam weighs 200 N, and the basket weighs 80 N. The calculated tension in the wire is 345.66 N, and the x-component of the force exerted by the wall is 172.83 N. Participants clarify the approach to finding the y-component of the force, emphasizing the importance of correctly applying torque and force balance equations.

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yb1013
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Homework Statement



A hungry bear weighing 720 N walks out on a beam in an attempt to retrieve a basket of food hanging at the end of the beam. The beam is uniform, weighs 200 N, and is 5.40 m long; the basket weighs 80.0 N.

a) When the bear is at x = 1.00 m, find the tension in the wire and the components of the force exerted by the wall on the left end of the beam.
N (tension)
N ( Fx)
N ( Fy)

The Attempt at a Solution



Okay well I sort of understood this question and created a balanced torque equation. After doing this I got that:

Tension = 345.66
Fx = 172.83

But I need help with finiding Fy Please.
I only have like one more chance to answer the question on my homework so I want to make sure I can get the right answer.
I know I have to write out some equation like maybe:

Rsin(theta) = 720 + 200 + 80 - 345.66sin(60)

Is this correct? And if its not, am I on the right track?
 
Last edited:
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is the beam supported by a horizontal string on each end?
 
Need more data on how the beam is supported.

Sounds like a cantilever beam with a tension wire at the other end, but is this tension wire vertical or anchored to the wall.
 
yb1013 said:
A hungry bear weighing 720 N walks out on a beam in an attempt to retrieve a basket of food hanging at the end of the beam. The beam is uniform, weighs 200 N, and is 5.40 m long; the basket weighs 80.0 N.

a) When the bear is at x = 1.00 m, find the tension in the wire and the components of the force exerted by the wall on the left end of the beam.
…
Tension = 345.66
Fx = 172.83

But when I go for Fy using 345sin(60), I keep getting 299 which my homework keeps telling me is wrong..

Hi yb1013! :smile:

I think you've calculated the y-component of the tension, instead of the y-component of the force at the wall. :redface:
 
would this be closer to the y-component for the force?

Rsin(theta) = 720 + 200 + 80 - 345.66sin(60)
 
what a dumb bear...

Anyways, I broke the componets into x and y directions. The y dir. is Tcos(theta) -mg =0 due to their being no motion.

also, their are 3 masses. bear, basket, and beam.
 
xxChrisxx said:
Its yogi bear...!

Thats some nice pic-a-nic

He's smarter than the average bear! :biggrin:
yb1013 said:
would this be closer to the y-component for the force?

Rsin(theta) = 720 + 200 + 80 - 345.66sin(60)

Yup … if the tension is right, then that looks right too! :smile:
 
  • #10
Ashleyz said:
what a dumb bear...

Anyways, I broke the componets into x and y directions. The y dir. is Tcos(theta) -mg =0 due to their being no motion.

also, their are 3 masses. bear, basket, and beam.


So would it go like 345.66cos(60) - 1020 = 0 ??
 
  • #11
tiny-tim said:
He's smarter than the average bear! :biggrin:


Yup … if the tension is right, then that looks right too! :smile:

Ok well the numbers in that question aren't actually my exact numbers, but with my numbers I come out with:

Rsin(theta) = 720.65

would that mean that its:

Rsin(60) = 720.65
R = 832.13

So 832.13 would be the force in the y-component??
I only have one more guess left on my homework, so I want to make sure lol
 
  • #12
yb1013 said:
So would it go like 345.66cos(60) - 1020 = 0 ??

uhh? :confused:

perhaps I misunderstood your Rsin(theta) …

I assumed you meant that to be the y-component of the reaction force at the wall:

Ry = 720 + 200 + 80 - 345.66sin(60)

(ooh, and it's 1000 not 1020 :wink:)
 
  • #13
tiny-tim said:
uhh? :confused:

perhaps I misunderstood your Rsin(theta) …

I assumed you meant that to be the y-component of the reaction force at the wall:

Ry = 720 + 200 + 80 - 345.66sin(60)

(ooh, and it's 1000 not 1020 :wink:)


Yea forget what I just said, I had a brain fart for a second there lol

Its just 720, sorry about the confusion.

Thanks again!
 
  • #14
yb1013 said:
… Its just 720 …

better check that …
 
  • #15
well its right, I stated in one of my other posts that the numbers were exactly what my actual problem contained. the 720 N of the bear is actually 740, which is why when I added all the numbers up I got 1020 instead of 1000.. So in the end the force is equal to 720

Sorry for all the confusion
 
  • #16
stuffing down more goodies than the average bear …

yb1013 said:
the 720 N of the bear is actually 740, which is why when I added all the numbers up I got 1020 instead of 1000.

ah :rolleyes: … heavier than the average bear! :biggrin:​
 

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