1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Angular motion ferris wheel

  1. Apr 14, 2013 #1
    1. The problem statement, all variables and given/known data
    Starting from rest, a ferris wheel of diameter 30.0m undergoes an angular acceleration of 0.040 rad/s^2. A certain rider is at the lowest point of the wheel just as it starts to move.
    a)find the velocity of the rider just as he completes a quarter of a turn.
    b)find the radial and tangential components of his acceleration at the same point.
    c)how much farther must the wheel turn before the rider attains a speed of 6.00m/s(the maximum that occurs during the ride)?

    2. Relevant equations
    v = ωr
    what other equations?

    3. The attempt at a solution
    circumference of ferris wheel is 94.2m and a quarter of that is 23.56m. 2pi is a circle and a quarter of that is pi/2. I have no idea how to do this. the answers from the back are
    a)5.32m/s up
    b)0.600m/s^2up and 1.88m/s^2 toward center
    c)24.6 degrees
  2. jcsd
  3. Apr 14, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Three more spring to mind.
    Are you familiar with a kinematic equation relating distance, acceleration and initial and final speeds (that's valid when acceleration is constant)? There is a completely analogous formula for angular movement.
    There is a formula relating angular acceleration to tangential acceleration (for constant radius) very similar to the one you quote for velocities.
    You will also need a formula for centripetal acceleration.
  4. Apr 14, 2013 #3
    yes. a = (ωF - ωI)/t . i don't know time

    Attached Files:

  5. Apr 14, 2013 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    You may not have been given time, but you have been given theta.
  6. Apr 14, 2013 #5


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Those equations each involve four out of the same five variables. Of those five, which three do you know and which do you want to find? Which equation does that mean you should use?
  7. Apr 14, 2013 #6
    ty i got it v = √2atheta x r = √2(0.04)(∏/2) x 15
    what do i do for question b and c
  8. Apr 14, 2013 #7
    never mind i know how to do question b. need help on question c
  9. Apr 14, 2013 #8
    never mind i figured it out ty bye
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted