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Simple force vector problem

  1. Jan 12, 2012 #1
    1. The problem statement, all variables and given/known data

    A child has weight 450 N. Whilst on a fairground ride the child is subject to a force P acting at 35° to the upward vertical, as shown in the diagram. Given that the resultant of P and the child’s weight acts horizontally,
    a. Find the magnitude of the resultant
    b. State the direction of the child’s acceleration
    c. Find the magnitude of the child’s acceleration

    2. Relevant equations

    3. The attempt at a solution
    My answers were the following
    a. 315 N (to 3 s.f.)
    b. The child’s acceleration is directed horizontally to the left
    c. 7.00 m(s^2) (to 3 s.f.)

    According to the textbook, my first two answers are correct, but the third is given as 6.86 m(s^2).
    How is this possible? a = F/m = 315 / 45 = 7 m(s^2). Did I miss something?
  2. jcsd
  3. Jan 12, 2012 #2
    forgot the diagram

    Attached Files:

  4. Jan 12, 2012 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    The book is using 9.8 m/s^2 for g, whereas you (apparently) used 10 m/s^2.
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