Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bio-mechanics Help! (Centripetal and Tangential acceleration)

  1. Oct 8, 2011 #1
    this is the question:

    Pick joint of the human body. With reference to this joint and the concepts of tangential and centripetal acceleration, provide an example and explain:

    A. an activity in which tangential acceleration is zero, centripetal is non-zero

    B. an activity in which centripetal acceleration is zero, tangential is non-zero.

    Any assistance would be greatly appreciated.
  2. jcsd
  3. Oct 9, 2011 #2


    User Avatar
    Gold Member

    You do know what tangential and centripital acceleration are, or is that where you are stumped.

    I would try to pick an activity or joint, and try to determine the forces their direction acting on that joint. Are the forces predominantly along the bones at the joint, or perpendicular to the joint causing a moment or twisting. There would have to b some movement of the joint. Just pushing on a wall may give a force on a joint but no acceleration.

    Activities are:
    running, jumping, weight lifting, horseback riding, throwing a ball, sitting, watching television, walking, picking a paperclip off the floor, playing on a swing, eating, race car driving, swimming, dancing, snapping your fingers, doing hula-hoop, typing on a keyboard, ...

    joints: knuckles, wrists, elbow, shoulder( ball socket), neck, jaw, spine, hip, ....

    Activity: running
    Joint: knee, thigh, ankle
    Acceleration at joint: centripital, tangential or both
    Explain :

    activity: weight lifting
    Joint: shoulder, elbow
    Accel : ??

    Last edited: Oct 9, 2011
  4. Oct 9, 2011 #3
    thanks for your help, I ended up digging up my physics book for a little refresher.

    I was having trouble visualizing how the forces with work with respect to the joints
  5. Oct 9, 2011 #4


    User Avatar
    Gold Member

    I think it is a tough problem, but say you want to build an artificial hand. You would need to know what forces are acting on the joints so it doesn't end up looking like that thing from "Hell Boy"
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook