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  1. E

    Please help with the last part of the problem

    A 3.49 kg ball is dropped from the roof of a building 187.2 m high. While the ball is falling to Earth, a horizontal wind exerts a constant force of 13.2 N on the ball. How long does it take to hit the ground? The acceleration of gravity is 9.81 m/s How far from the building does the ball...
  2. L

    ____What is What is Not Part 2_________

    Best to read the first part but basically we deduced that in 2018 there is not a correct definition of Up or Down that fits current science. Frankly it is below bad when science cannot even define Up and Down when? Answer this: Why should I believe science when it cannot even define Up...
  3. A

    Deriving equations (3 part question!)

    I need help with all the following and will post under each what I believe the answer is. Thank you in advance! A body of mass m accelerates uniformly from rest to a speed of V in total time T. (a) Mathematically derive an equation for the work done on the body as a function of time T. W=...
  4. P

    I need help with the final part of a long momentum problem

    This question has 4 parts. I managed to do a) to c) but I can't figure out d) at all. A student is throwing bricks at his physics teacher. The bricks have a mass of 2 kg and the student can throw them with a speed of 10 m/s. The teacher is standing on a frozen lake so there is no friction and...
  5. T

    Perturbation approach to solve attractive part of Lennard-Jones potential

    The text is taken from this site: http://www.chem.konan-u.ac.jp/PCSI/web_material/LJ.pdf I don't get the definition added just after (7). Where is it taken from and what does it mean? Why is it the energy? And can someone show the arithmetics and the fundamental principles on how to get from...
  6. Y

    Please help with this derivation on part of the retarded potential

    I cannot do it with Latex, so I have to up load with image!! I have to actually go to physics forum, type in the Latex there and then copy on to Woed, then scan and then upload onto Tinypic to put it on here. If you have any better idea to do Latex direct here, that would save a lot of time...
  7. J

    The convergent mirror in this problem is a part of...

    Please help me with this question? a) Hint: The convergent mirror in this problem is a part of a lens/mirror system so the object in this problem may be either real or virtual. Construct a ray diagram. Given: A real object is located to the left of a convergent mirror. The object's distance...