Recent content by Shaku
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Circular Motion, Massless String - Swinging Rock
Alright, I'm glad I started with the easier set of coordinates. Thank you for all the help!- Shaku
- Post #25
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Alright. One last question, If I had used the vertical axis as my y-axis, and horizontal axis as my x-axis, would I just find the tensionx and tensiony and take the pythagorean theorem to find the tension? Ex: Fnety = Tsinθ - mg Fnetx = Tcosθ Tysinθ - mg = mv2/r Txcosθ = mv2/r Ty...- Shaku
- Post #23
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Fnetx = mat mgCosθ = mat gCosθ = at Would this be the correct usage of the equations?- Shaku
- Post #21
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Okay, that makes sense. For part d, where the problem asks top find the tangential acceleration, I know that there are two equations I can use: at = w/t or at = L*alpha. From the diagram, wouldn't it just be gCosθ? I'm not sure how to actually use these equations to get an answer though, as I...- Shaku
- Post #19
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
I was just looking over my work, and I noticed that I didn't quite understand why you said T - mgsinθ was the net force in the Y direction. If my axis was horizontal and vertical, it would be Tsinθ - mg, but I had set my axis is along the path of motion. I'm confused how you got your...- Shaku
- Post #17
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Okay, that clarifies things after making a visualization of the situation. T = (mv2)/L + mgSinθ T = (m(2g*LSinθ)/L) + mgSinθ T = m((2g*Lsinθ)/L + gSinθ)- Shaku
- Post #15
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Ohhh, okay. That makes sense now. Since there is no velocity at any point in the path, that would mean there is also no acceleration, so: Fnety = 0 T - mgSinθ = 0, thus Fnety=mv2/r would just be 0. Since Fnety is 0, Fnetx = Fnet So mgCos = mvx2/L ... But I'm pretty sure I did something...- Shaku
- Post #13
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
This is how I have it set up: From this, how do I set up my equation to find the tension without breaking it into components? Forces in the Y direction: T-mgSinθ Forces in the X direction: mgCosθ- Shaku
- Post #11
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
I'm trying to use Fnet = mv^2/r. The net force in the x direction is mgCosθ and the net force in the y direction is T - mgSinθ. I plugged each respective net force into the equation to solve for vx and vy, and then took the Pythagorean theorem to find V as a single vector instead of it being...- Shaku
- Post #9
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Alright, cool! So now that I have the velocity, I can solve for the tension by using the same equation as I used to find velocity before, but this time solving it for T (*note, this is with corrections): \sqrt{LgCosθ} = vx \sqrt{L(T-mgSinθ)/m} = vy So, solving for V I'd get: V =...- Shaku
- Post #7
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
Ah, thanks for catching that. I had my axis set up with with tension along the y-axis, so I got confused when I determined the sin/cos values. I currently have v = \sqrt{2gL} How would I factor the angle into that? Would it be v = \sqrt{2g*Lsinθ}? (I just looked at the triangle the angle...- Shaku
- Post #5
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
I used Fnetx = mgsinθ Fnety = T - mgcosθ plugged those into two separate equations mgsinθ = mvx^2/r and T-mgcosθ=mvy^2/r solved for v and found \sqrt{LgSinθ} = vx \sqrt{L(T-mgCosθ)/m} = vy then used the Pythagorean Theorem to find V. Ki + Ui = Kf + Uf I know that the initial kinetic energy...- Shaku
- Post #3
- Forum: Introductory Physics Homework Help
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Circular Motion, Massless String - Swinging Rock
1. Homework Statement : A rock of mass m is attached to a string of negligible mass and length L. The rock is released from rest from a horizontal position. When the rock is at point P, the string attached to the rock makes an angle θ with the horizontal. In terms of the quantities, m, L, θ and...- Shaku
- Thread
- Circular Circular motion Massless Motion Rock String
- Replies: 24
- Forum: Introductory Physics Homework Help
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Wood-block Friction Launch Problem
It's negative, but that wouldn't change much in my final answer. Just an extra minus sign out front, and it's saying that that's wrong too. Edit: Actually, it wouldn't change the answer at all as I had already done the calculations as if they were with a negative acceleration (I just wrote it...- Shaku
- Post #12
- Forum: Introductory Physics Homework Help
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Wood-block Friction Launch Problem
I found an example from my notes that is pretty similar to this question, and it had the equation: gSin∅ + MkgCos∅ = a as well, so I'm not sure where I'm going wrong. I fixed my arithmetic (which wasn't actually an error, I just didn't write it up on the post correctly), and I did the exact...- Shaku
- Post #10
- Forum: Introductory Physics Homework Help