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alexyn

A child pulls a 15-kg sled containing a 5.0-kg dog along a straight path on a horizontal surface. He exerts a force of 55 N on the sled at an angle of 20° above the horizontal, as shown in the figure above. The coefficient of friction between the sled and the surface is 0.22. a. Calculate the normal force of the surface on the system. b. Calculate the acceleration of the system. c. Calculate the work done by the child's pulling force as the system moves a distance of 7.0 m

  • one year ago
  • one year ago

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  1. alexyn
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    d. At some later time, the dog rolls off the side of the sled. The child continues to pull with the same force. On the axes below, sketch a graph of speed, v, versus time, t, for the sled. Include both the sled's travel with and without the dog on the sled. Clearly indicate with the symbol tr the time at which the dog rolls off.

    • one year ago
  2. ksaimouli
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    can u do me a favor can u draw the diagram

    • one year ago
  3. alexyn
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    sure

    • one year ago
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  4. ksaimouli
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    what part u r struck

    • one year ago
  5. ksaimouli
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    ok so (a) FN=mg-Fsin 20

    • one year ago
  6. alexyn
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    Part D

    • one year ago
  7. ksaimouli
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    i am sorry i am weak at graphs :-(

    • one year ago
  8. ksaimouli
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    @ivanmlerner can u help her please

    • one year ago
  9. alexyn
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    thanks for trying though

    • one year ago
  10. ivanmlerner
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    It is only in part d that you need help?

    • one year ago
  11. alexyn
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    yes. please

    • one year ago
  12. ivanmlerner
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    Ok, you know the aceleration before the dog jumps out, so you can draw the graph of v until that moment by using the aceleration as the slope of the line because it is the rate of change of the velocity. Do you understand it so far?

    • one year ago
  13. alexyn
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    Yes.

    • one year ago
  14. alexyn
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    Im unsure about the acceleration. I got 0.07 m/s. Is that right?

    • one year ago
  15. ivanmlerner
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    Just to be sure, what number are you considering for g?

    • one year ago
  16. ivanmlerner
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    10 or 9.8?

    • one year ago
  17. ivanmlerner
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    I'll be back in a few minutes but I got 0.43 with 9.8

    • one year ago
  18. alexyn
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    -10

    • one year ago
  19. alexyn
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    ok. I got 1.64 m/s now

    • one year ago
  20. furnessj
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    So, I had a go at this, I get a) 177.4N b) 0.63 m/s/s c) 362J As for d) - the question says to sketch, so you do not need values. You just need to realise that with less mass but the same force, the acceleration will be greater, so the slope must get steeper: |dw:1352244868726:dw|

    • one year ago
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