Energy: Block sliding down frictionless ramp

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Homework Help Overview

The discussion revolves around a physics problem involving energy conservation as a block slides down a frictionless ramp. The original poster presents specific speeds at two points on the ramp and seeks to determine the speed at a second point given a different initial speed.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the principles of kinetic and potential energy to relate the speeds at different points on the ramp. They express confusion regarding the height assumptions made in their calculations.

Discussion Status

Some participants have offered responses to the original poster's inquiry, but there is a request for further elaboration on the reasoning behind those responses. The discussion appears to be ongoing, with multiple interpretations being explored.

Contextual Notes

The original poster acknowledges a misunderstanding regarding the height at point B, indicating a need for clarification on assumptions related to the problem setup.

basenne
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1. In Figure 8-49, a block is sent sliding down a frictionless ramp. Its speeds at points A and B are 1.90 m/s and 2.60 m/s, respectively. Next, it is again sent sliding down the ramp, but this time its speed at point A is 3.85 m/s. What then is its speed at point B?

W0150-N.jpg

Figure 8-49




2. KE = 1/2mv^2

PE = mg (h)




3. 1/2(m)(2.2^2) + m(9.8)(h) = 1/2(m)(2.6^2) + m(9.8)(.5h)

Yes, I know now that I can't assume that the height for point b is .5 of the height for point A. I'm totally lost on this question and I'd really appreciate a push in the right direction.
 
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Note: answer deleted by moderator.
 
Last edited by a moderator:
Umm, I really appreciate the answer, however, would you care to elaborate how you got it?

And yeah, you're correct. (Although there was never any doubt that you wouldn't be :D)
 
Note: detailed solution deleted by moderator.
 
Last edited by a moderator:

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