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Homework Help: Spring, Block, KE, PE, Incline Problem: Why is KE=ZERO?

  1. Nov 5, 2012 #1
    Spring, Block, KE, PE, Incline Problem: Why is KE=ZERO??

    A 250 g block is pressed against a spring of force constant 1500 N/m until the block compresses the spring 8.0 cm. The spring rests at the bottom of a ramp inclined at 60.0 degrees to the horizontal. Using energy considerations, determine how far up the incline the block moves from its initial position before it stops if:

    a) the ramp exerts no friction force on the block

    b) if the coefficient of kinetic friction is 0.400




    Can someone explain to me why is the change in kinetic energy = to zero??



    The solutions says KE is zero because initial and final states are stationary. What does that mean? Doesn't the box move...

    Maybe I don't fully understand the concepts...

    Answers:
    a) 2.26 m
    b) 1.84 m
     
  2. jcsd
  3. Nov 5, 2012 #2
    Re: Spring, Block, KE, PE, Incline Problem: Why is KE=ZERO??

    When you start, your velocity is zero, when you stop it's zero again.
     
  4. Nov 5, 2012 #3
    Re: Spring, Block, KE, PE, Incline Problem: Why is KE=ZERO??

    Ohhh! I see! Wow that was a quick reply to my first post ever. Hahaha thanks a bunch! x3 :!!)
     
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