Recent content by _h2tm

  1. H

    Power input of a Force acting on a particle moving with Velocity

    OK, thanks. I completely get how to do this in the future. Regarding your second comment though -- I understand about arctan. I drew a diagram so I knew where my vectors were. Was this comment just FYI or was my attempted method something that would work, I was just simply doing it incorrectly?
  2. H

    Power input of a Force acting on a particle moving with Velocity

    Homework Statement Find the power input of a force \vec{F} acting on a particle that moves with a velocity \vec{V} for each of the following situations. \vec{F} = 4\hat{i} N  + 3\hat{j} N , \vec{V} = 7\hat{i} m/s  \vec{F} = 7\hat{i} N  - 5\hat{j} N , \vec{V} = -5\hat{i} m/s...
  3. H

    What is considered a small velocity?

    Maybe try looking up the average speed of an elevator and take half of that ... or just go with .01 m/s.
  4. H

    Scalar product to prove triangle inequality?

    I may not be understanding your question, but it seems like you should start with the Pythagorean Identities.
  5. H

    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    What I wrote above included | & | to indicate taking the absolute value and gave the correct result (at least the answer that the website was looking for). I'm not seeing how I can manipulate the sum of the forces so it would be R(g - .35g).
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    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    After getting more information from my teacher, here is the solution for the "smallest" value, i.e. the speed at the bottom of the roller coaster: Assume Fsp = .35mg at the bottom of the roller coaster as well the top. Fsp - mg = mv2/R .35g - g = v2/R √|R(.35g - g)| = v The question...
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    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    When I entered the answer (we use WebAssign for our homework), it showed as correct in the space that said "largest value" :).
  8. H

    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    Yes. I copied & pasted the problem: The "largest" value is the one I found above (≈13.62 m/s).
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    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    We haven't covered conservation of energy yet (we've just finished Newton's laws, friction, uniform circular motion, drag forces, and an intro to work and dot-products). I sum the forces at the bottom of the roller coaster: ƩF = Fsp - mg = mv2/R ∴ Fsp = m[(v2/R) + g] I don't know the...
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    How Do You Calculate the Second Speed of a Roller Coaster at the Loop's Top?

    Homework Statement The radius of curvature of a loop-the-loop for a roller coaster is 14.0 m. At the top of the loop, the force that the seat exerts on a passenger of mass m is 0.35mg. Find the speed of the roller coaster at the top of the loop. (Enter your answers from smallest to largest.)...
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