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Urgent - Loop de Loop problem, Normal Forces

  1. Oct 18, 2013 #1
    1. The problem statement, all variables and given/known data

    In Fig. 8-28, a small block of mass m = 3.0 kg can slide along the frictionless loop-the-loop. The loop has radius R = 0.80 m. The block is released from rest at point P, at height h = 2.9R above the bottom of the loop.

    I attatched a picture

    (a) Find the speed of the block when it reaches point Q.

    (b) Find the normal force on the block at point Q.

    (c) Find the normal force on the block when it is at the very bottom.

    (d) Find the normal force on the block when it is at the top of the little loop (i.e., at a height 2R above the ground)

    2. Relevant equations

    KEi + PEi = KEf +PEf


    v = w (r)

    3. The attempt at a solution

    So for the velocity isnt it just converting the PE at the top for the KE at the bottom?

    For all the normal forces i am completely stumped

    Attached Files:

  2. jcsd
  3. Oct 18, 2013 #2
    So for a) v = 3(.98) 1.9(.8) = 1/2(3)v^2
  4. Oct 18, 2013 #3


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    Homework Helper

    hi gcharles_42! :smile:

    but i don't understand the LHS of your equation :redface:
    for the normal forces, you need to use Ftotal = ma in the normal direction

    (you'll need the centripetal acceleration formula)
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