Recent content by marthkiki

  1. M

    Finding the work done using force vectors in 3 dimensions

    Wait where does the magnitude of 3 N come into play? Shouldn't it be multiplied to 2j to get the total work? So you get W = F*AB AB = 2j F = 3(2i + j + 2k) = 6i + 3j + 6k F dot product AB = 0 + 6j + 0 = 6j. So the work should in fact be 6 Joules, correct?
  2. M

    Finding the work done using force vectors in 3 dimensions

    s That may well be true. If so, is the correct answer 2? The displacement vector is 2j. (2i + j + 2k) dot product 2j = 0 + 2j + 0 = 2j. So the correct answer is 2 Joules, correct?
  3. M

    Finding the work done using force vectors in 3 dimensions

    Positive. This really doesn't make any sense to me.
  4. M

    Finding the work done using force vectors in 3 dimensions

    Homework Statement Find the work done by a force of 3 Newtons acting in the direction 2i + j + 2k in moving an object 2 meters from (0, 0, 0) to (0, 2, 0). Homework Equations Commonly known vector operations. The Attempt at a Solution I found the displacement vector to be 2j...
  5. M

    Solve for v: "How to Solve for v with Theta, g, and x

    Thank you so much! I get it now. I totally squared the left wrong.
  6. M

    Solve for v: "How to Solve for v with Theta, g, and x

    If i do that, I end up with x = 86612.49 and y = 4.165. I then end up with v^4 - y^2 = v^4 - x, which again gets me to -y^2=x.
  7. M

    Solve for v: "How to Solve for v with Theta, g, and x

    If i do that, I end up with u = v2 + 416.2 then the discriminant will end up negative leaving me with an imaginary velocity. Did I do this correctly?
  8. M

    Solve for v: "How to Solve for v with Theta, g, and x

    By squaring both sides, I get v^2 - 17.35 = v^4 - 86612.49. That gets me -17.35 = -86612.49. Is this what you mean by a false answer?
  9. M

    Solve for v: "How to Solve for v with Theta, g, and x

    Homework Statement theta = tan^-1 {{v^2 - [v^4-g(gx^2)]}^1/2}/gx I know that x is 30, theta is 45, g is 9.81 m/sec^2. I'm trying to solve for v. Homework Equations The Attempt at a Solution I've gotten all the way down to v^2 = (v^4-86612.49)^1/2 + 4.165 What do I do from here?
  10. M

    Gravity from spacetime curvature

    After a while of trying to understand this, it's still kind of confusing. I get how the planets orbit around the sun because of the sun's spacetime curve, but if one were to drop something, how does spacetime curvature cause it to fall? How can everything in the universe have a gravitational...
  11. M

    What is the hardest question to ask a quantum physicist?

    Unify quantum mechanics and relativistic physics in a perfect theory.
  12. M

    Violation of conservation of energy by expansion of the universe

    I was watching this video, and it was saying that because the universe is expanding, the wavelengths of light waves were elongating, and therefore the energy of radiation throughout the universe is decreasing. They said that this defies the conservation of energy, but Einstein's general theory...
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