- #31
crpcrpcrp
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is the initial velocity=0ms-1
Kinetic and potential energy and speed
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Homework Help Overview
The discussion revolves around kinetic and potential energy in the context of two problems: one involving an object dropped from a height and the other concerning a roller coaster car moving along a track. Participants express confusion about the concepts and calculations related to energy conservation.
Discussion Character
- Exploratory, Conceptual clarification, Mathematical reasoning
Approaches and Questions Raised
- Participants attempt to understand the relationship between kinetic and potential energy, questioning how to determine when these energies are equal. They explore the concept of total energy conservation and discuss the initial conditions of the problems.
Discussion Status
Some participants have provided insights into the conservation of energy and the types of energy involved, while others are still seeking clarity on specific calculations and concepts. There is an ongoing exchange of ideas, with some guidance offered on how to approach the problems.
Contextual Notes
Participants mention a lack of prior instruction on the topics, which contributes to their confusion. There are references to specific values and assumptions, such as the height from which the object is dropped and the mass of the roller coaster car, but some participants express uncertainty about these details.
- #32
Hootenanny
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Correct! So since the object is at rest before it is dropped, all the energy is in the form of potential energy. So the constant in our equation must be...crpcrpcrp said:
- #33
crpcrpcrp
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0?
- #34
Hootenanny
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If the total energy of the object must be constant then the total energy must be the same as the total energy at the start. Does that make sense?crpcrpcrp said:0?
- #35
crpcrpcrp
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I understand
- #36
Hootenanny
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Good, so now we have
2*potential energy = constant
2mgh = 20mh = 100m
20h = 100
Can you now go from here?
2*potential energy = constant
2mgh = 20mh = 100m
20h = 100
Can you now go from here?
- #37
crpcrpcrp
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i'm still a little confused. so what would be the constant?
- #38
crpcrpcrp
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Hootenanny said:
what do i do form here?
- #39
crpcrpcrp
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wait...
where did u get the 100?
where did u get the 100?
- #40
Hootenanny
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The constant would be the 100m as you stated yourself.crpcrpcrp said:
You should solve for h, the height of the ball when the potential energy is equal to the kinetic energycrpcrpcrp said:what do i do form here?
You derived it yourself;crpcrpcrp said:
crpcrpcrp said:
- #41
wisienkas
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at starting height you know that potential energy = constant
you know the constant is potential energy + kinetic energy.
therefore the potential energy and the kinetic energy is the same if 2*potential energy=constant
you can therefore say constant/2 = potential energy or constant/2= kinetic energy
since you get the potential energy from gravity*mass*height you can simply just isolate the height since you have te energy from the constant.
its more math than physics however. hope it helps for any looking in here
you know the constant is potential energy + kinetic energy.
therefore the potential energy and the kinetic energy is the same if 2*potential energy=constant
you can therefore say constant/2 = potential energy or constant/2= kinetic energy
since you get the potential energy from gravity*mass*height you can simply just isolate the height since you have te energy from the constant.
its more math than physics however. hope it helps for any looking in here