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!

Question about torque

  1. Apr 10, 2007 #1
    When expressing torque as a vector, it is perpendicular to the lever (the exact direction is determined by the right hand rule).

    But why is it so? this vector can not be a force vector since the angular force that causes the rotation is the force produced to the lever. So what does the direction of the torque signify?
  2. jcsd
  3. Apr 10, 2007 #2


    User Avatar

    the direction of torque, like the direction of rotation is such a direction that lies alongside the axis of rotation. spin it in one direction and the torque or rotation vector lies alongside the axis pointing one way, spin the other sense and the vector lies alongside the axis pointing the opposite way. which direction of vector that gets associated with which sense of spin is only a matter of convention. just like right-handed threaded screws vs. left-handed threaded screws. they had to pick one and the right hand rule was picked over the left hand rule.
  4. Apr 10, 2007 #3
    The direction of torque signifies just that- the direction of torque.
  5. Apr 12, 2007 #4


    User Avatar
    Homework Helper

    The direction of a torque vector is the axis. It's not a force vector. You'd need to invent the concept of a circular force vector to deal with torque, which would be messy. Using left or right hand rule, the vector direction is the same as the axis of the circular force vector.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook