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Homework Help: Velocity along a frictionless surface

  1. Apr 13, 2016 #1
    1. The problem statement, all variables and given/known data
    A body moves down along an inclined plane from A(top) to B(bottom), and then moves on the floor in continuation to some point C. (All surfaces are frictionless)

    After reaching B, body is having some acceleration. But while moving from B to C,
    a) will it keep on accelerating,
    b) or, its acceleration will be zero (constant velocity) from B to C.

    2. The attempt at a solution
    Frictionless surface don't interfere with the motion of the body, so whatever state body is possessing at B (some velocity), this will continue holding, so body will move with zero acceleration from B to C.
  2. jcsd
  3. Apr 13, 2016 #2


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    I agree with your solution.

    The question sounded a bit odd, "After reaching B, body is having some acceleration."
    I would say, "Up to point B, body is having some acceleration."
  4. Apr 13, 2016 #3
    Body is having acceleration at B as it has accelerated from A to B, question is about from B to C.
  5. Apr 13, 2016 #4
    The speed will remain constant from B to C
    Because B and C are on the same horizontal level
    And thus there's no question of vertical motion here (they surely aren't going to break the floor and move :))
    And since the horizontal components of the forces acting on the block (gravity and the normal force) are zero
    And since there's no friction
    The block will keep moving with a constant velocity from B to C

  6. Apr 14, 2016 #5
    I was confused about the acceleration part.
  7. Apr 15, 2016 #6
    Don't be then :)
    The block accelerates from A to B because as there's no friction,the force mgsinθ which acts down the incline,accelerates the block
    Over the entire distance the block traverses/moves
    Once it reaches B,there is a momentary transition and there's some initial acceleration from B to C
    But its momentary and thus it can be neglected!

  8. Apr 23, 2016 #7
    Like others have, the speed of the body from B to C will remain constant since there's no force acting on it due to gravity.
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