Recent content by sojsail

  1. sojsail

    Gravitation (planetary motion)

    Is it possible that your sketch is a misinterpretation of the problem description? If p is on the orbit, when the particle comes around to the location of p, the force would become infinite (with n being a negative exponent). I am assuming that r is the distance to p. And in that case, I can not...
  2. sojsail

    Acceleration graph

    In graphs of a thrown ball, assume that time starts when the ball leaves the hand. So would the acceleration of the throwing motion be part of the graph?
  3. sojsail

    Acceleration graph

    If you are confused by what is said in any of our posts, likely any of us that are connected could explain/reword the post for you. We don't explain how to get the answer, but if necessary we can explain posts that have come in for you.
  4. sojsail

    Newton's Second Law — Net Force problem

    I think your solution is equivalent to one of a list of perhaps 2 or 3 methods that would get full credit. One quibble about your worksheet: in one line you gave g as the unit where I think you knew, from how you converted the numerical part, is kg. That could cost you. There were several...
  5. sojsail

    Velocity-time graph

    Could it be that you intended to ask about acceleration?
  6. sojsail

    Why can we ignore certain circuit paths?

    I found this to be an interesting discussion. I can not tell if the worry has been eliminated, so I would like to add my way of seeing that. Current would be flowing down the schematic thru R1. Let the potential of the "horizontal wire" be Vh. What if some current tried to continue going down...
  7. sojsail

    Forces and vectors: pulling a baby buggy on soft ground

    Where did the 64 come from? Certainly not the 64 N in frame #8. In which direction are you now trying to work out the total force -- total force exerted on the ground?
  8. sojsail

    Kirchhoff's law problem with two batteries

    Another approach: You know that the ammeter reading is to be zero. So assume that is the case and simplify your equations accordingly.
  9. sojsail

    How is the moment at A using the Force 1200N calculated?

    You are asked to find moment of this Force about point A. Don't assume the bracket is going to rotate to a new position. This would be an analysis of the twisting torque on the bracket (perhaps to see how strong the bracket needs to be considering what will be applied to it in use). Doc Al said...
  10. sojsail

    Time it takes to swim across a river

    I am back. I see that Orodruin caught me misreading the problem. He swims at 4 kph, so the minimum time to the opposite shore would be 540 s. So the book's 624.3 s may be right Edit: since the landing point is to be exactly opposite. Picture yourself at the bank of the river about to jump in...
  11. sojsail

    Time it takes to swim across a river

    I need to sign off for tonight. I hope someone else will take up monitoring and aiding your progress.
  12. sojsail

    Time it takes to swim across a river

    Doc Al said Doc Al's "at an angle" means not perpendicular. Your vertical and horizontal sides would be perpendicular, would they not?
  13. sojsail

    Time it takes to swim across a river

    OK, please describe your triangle.
  14. sojsail

    Time it takes to swim across a river

    Here is a nudge: Review Doc Al's post #8.
  15. sojsail

    Time it takes to swim across a river

    Yes, there is an error somewhere. Before we knew that the goal was to go straight across the river, I worked it out assuming all of his speed would be dedicated to getting across the river quickly. That would yield the minimum time considering his speed and width of the river. That time was 1080...