Recent content by Jbum

  1. J

    The relativity of time: time dilation

    yes, i am aware of that thanks. i just happened to accidentally post it in the same thread, but did not know how to remove it.
  2. J

    The relativity of time: time dilation

    QUESTION #1: 1. suppose a race on Earth was monitored by a spaceship traveling in space at 0.900c relative to the Earth and the space travelers measured the time of the race to be 125.6s. What was the time recorded on earth? 2. t = gamma t' where gamma = 1/ sqrt(1-v squared/c squared) 3. v...
  3. J

    Work done during sandpaper application on horizontal surface

    1. a table is being sanded. in the process, the sandpaper is rubbed back and forth 30 times over a distance of 0.6m. it is pressed against the table with a normal force of 1.5N, and the coefficient of kinetic friction is 0.85. how much work is being done by the kinetic frictional force during...
  4. J

    Waves and light (conceptual questions)

    yes thank you. i consulted a solution text for those two problems so they are now solved.
  5. J

    Waves and light (conceptual questions)

    [SOLVED] waves and light (conceptual questions) hey, i have a few conceptual questions related to waves and light. 1. what is the ratio of thickness of crown glass and water that would contain the same number of wavelength of light? (index of refraction for glass = 1.52, and for water, it's...
  6. J

    Theory of special relativity (conceptual problems)

    thanks again, problems solved. I've asked others too and I've finally gotten all the clarification and answers i $needed to answer those 4 questions. thread is now closed: problem solved.
  7. J

    Theory of special relativity (conceptual problems)

    thank you for that. 1. that is what i was thinking too, prior to what i wrote above. however, is is really impossible to answer this question in context of the theory of special relativity? are you sure? 2. i know much about time dilation (and that time in general is all relative, there is...
  8. J

    Help with kinematics equations (d = v t and the projectile one)

    v falling and v projected are, however, the same. as mentioned before, they start from rest. therefore v=0 for both balls and this vfalling t and vprojected t can be automatically cut out. this topic is, by far, getting somewhat too complicated and moving away from the question that i would...
  9. J

    Theory of special relativity (conceptual problems)

    [SOLVED] theory of special relativity (conceptual problems) hi all, I've got a few physics questions for you to put some thought into and perhaps to share some expertise with me also... i'm currently studying about the special theory of relativity and I've got a few conceptual questions that...
  10. J

    Help with kinematics equations (d = v t and the projectile one)

    dotman, when i set them equal to each other i meant to have one equation representing the falling ball and one representing the projected ball. i didnt use subscripts to label them because i have not any clue on how to do that. but the leftside represents the falling ball and the right side is...
  11. J

    Basic kinematics equations question

    love the link, but unfortunately y = y + vt + 0.5at(squared) confuses me more as i have learned y = vt + 0.5at(squared). i have never seen such an equation as the one in that link in my life. it's not that i don't believe it, it's just that i'd rather learn in terms of the equations i have been...
  12. J

    Help with kinematics equations (d = v t and the projectile one)

    the reason that the "(v + 1/2at)" can simply cancel out is because both balls initially start at rest (where v = 0) and both balls experience the same rate of acceleration when they are "let loose". does it then make sense to cancel out "(v + 1/2at)" from both sides of the factored equation...
  13. J

    Help with kinematics equations (d = v t and the projectile one)

    well, since you need to consider acceleration for both balls, then the equation d = v t + 1/2 a t(squared) should apply to both also. therefore, since d = d: v t + 1/2 a t(squared) = v t + 1/2 a t(squared) t(v + 1/2at) = t(v + 1/2at) after factoring the ts the "(v + 1/2at)"...
  14. J

    Help with kinematics equations (d = v t and the projectile one)

    the reason one ball is projected and one isn't is because i wanted to prove that whether a ball drops straight down or is projected, they will hit the ground at the same time. this being said, my point of projecting one of the balls is to also show that the horizontal direction that it travels...
  15. J

    Help with kinematics equations (d = v t and the projectile one)

    many thanks to your efforts in trying to aid me and i understand all that you have written above, but it does not fully answer the question that i was orginally implying. i'll take it as my fault. however, let me rephrase and re-explain the situation: - i have made this apparatus which...
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