- #1
mtayab1994
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Homework Statement
Look at the attachment
Please tell me if there is anything wrong with my work because apparently my teacher thinks its wrong.
Kinetic energy and potential energy work
- Thread starter mtayab1994
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Homework Help Overview
The discussion revolves around a physics problem involving kinetic energy, potential energy, and the calculation of work and speed at different points along a ramp. Participants are trying to clarify the problem statement and the relationships between the given variables.
Discussion Character
- Exploratory, Assumption checking, Problem interpretation
Approaches and Questions Raised
- Participants are attempting to clarify the problem requirements, specifically what is being asked regarding the calculations for work, tension, potential energy, and speed at various points. There is a focus on the relationship between the given speed at point B and the calculated speed at point C.
Discussion Status
The discussion is ongoing, with participants exploring different interpretations of the problem. Some have provided guidance on checking calculations and assumptions, particularly regarding the speed at point B. There is a recognition of differing values for speed, leading to further questioning of the problem setup.
Contextual Notes
Participants note that the problem involves translating terms from another language, which may affect clarity. There is also mention of specific values given in the problem, such as distances and speeds, which are being used to derive other quantities.
Look at the attachment
Please tell me if there is anything wrong with my work because apparently my teacher thinks its wrong.
- #2
Doc Al
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Can you please state the problem and what you are asked to find?
- #3
mtayab1994
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Doc Al said:
1. calculate the work of W.
2. calculate the tension or w.e its called of T.
3. a/ write the potential energy in terms of m,g,r',and Zc
b/ find the speed of the body (s) at the point β=60°
sorry I'm learning this stuff in a different language so I'm just translating it by myself.
Last edited:
- #4
Doc Al
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I'm a bit puzzled by the problem. You are given both the distance traveled and the speed at point B? (Seems like you should be able to calculate the speed given the distance.)
- #5
mtayab1994
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Doc Al said:
yea i did solve it and it came out to 2m/s and everything else is correct and i don't know how my teacher thinks its wrong.
- #6
mtayab1994
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Doc Al said:
Yea i did solve the speed at the point c when it has traveled 60° on the ramp. Everything is on the paper i just want to know if there is anything wrong with it.
- #7
Doc Al
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I did not solve for the speed myself, but it seems as if you're saying that it comes out to be 2 m/s. Yet on your sheet it seems to be given as 3 m/s. Something's wrong somewhere.mtayab1994 said:
Did the statement of the problem include the speed at point B?
- #8
mtayab1994
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No that speed is for when the body is at the point B. We have to find the speed of it when it's at point C.
- #9
Doc Al
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Once again I ask: Are you given both the distance AB and the speed at point B? (If so, you should check that the speed at B is correct by solving for it directly.)mtayab1994 said:
- #10
mtayab1994
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Doc Al said:
Yes i am given AB=1m and Vb=3m/s but the question was to find the speed at the point C.
And i used the law of conservation of mechanical energy to solve for the speed at the point c and i got 2m/s. You are given 3m/s just so you use it to solve for c.
- #11
Malor
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For the speed at point B try the following:
EpotA = EkinB
mgh = m/2*v²
v = sqrt(2gh) (h=0,5m)
Check what you did differently, and that's where you went wrong.
EDIT: Ah... Energy at point C... oops.
EpotA = EkinB
mgh = m/2*v²
v = sqrt(2gh) (h=0,5m)
Check what you did differently, and that's where you went wrong.
EDIT: Ah... Energy at point C... oops.
- #12
mtayab1994
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Malor said:
no man i don't need the speed at the point b i need the speed at point c where i found it to be 2m/s. I don't know why you guys think i need to find the speed at b. I was given that stuff on the top right corner of the paper.
- #13
Doc Al
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Did you check that Vb = 3 m/s is correct? My point is that given AB = 1m, you should be able to solve for Vb. They shouldn't have to give it to you.mtayab1994 said:
- #14
mtayab1994
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Doc Al said:
Ok i'll check the speed at b right now and we given the speed at the point b so we can use it to find the speed at c and is my speed for c correct?
- #15
Doc Al
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Assuming that the speed at B is correct, then the speed you calculated for point C seems correct to me.mtayab1994 said:
- #16
mtayab1994
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i found the speed at b is 3.16m/s but he gave it to us as 3m/s.
- #17
mtayab1994
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Doc Al said:
Yea that's all i wanted to know, he just counted it wrong for me for no reason.
- #18
Malor
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With
Erad = 1/2 Jω², ω=v/b, b=2/6∏r
EkinB - Erad - EpotC = EkinC
=> vB²-2r²(v²/((2/6)∏r)²-2gh=v² => v=1.32m/s says my calculator
Erad = 1/2 Jω², ω=v/b, b=2/6∏r
EkinB - Erad - EpotC = EkinC
=> vB²-2r²(v²/((2/6)∏r)²-2gh=v² => v=1.32m/s says my calculator
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- #19
mtayab1994
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Malor said:
deleted what?
- #20
Malor
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mtayab1994 said:
I deleted something that I thought made no sense and replaced it with what I think the answer to be ;p
h = cos 60 * r
Because at point C, the object has kinetic, potential and rotational Energy.
- #21
mtayab1994
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Malor said:
I don't think so because the answer is 2m/s.
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