L33 - Torque & Rotation Tutorial #6

• Torque Rules:

  • T = F * r

  1. Only perpendicular component of force with cause rotation
  2. Magnitude = force x radius from axis (check)
  3. Rotation will be positive or negative = right hand rule
• Torque = rotational effect of force
• Direction of rotation & torque vector:

  • Right hand rule
  • Fingers in direction of force ie, direction of rotation
  • Thumb points in direction of torque vector (ie perpendicular to plane of rotation
  • CCW = positive
  • CW = negative
• Torque is when a force is applied away from the CoM
• • Resistance force = neg torque
  • Muscle force = pos torque
• Direction of rotation & torque vector:

  • Vectors all point in positive directions
  • Cross onto u to get z (cross product)
  • Wraps fingers to y, thumb point in z direction
  • Continue moving counter clockwise (CCW)
  • y to z gives you x
  • z to x gives you y
  • Any point in that space in positive reference frame
  • Negative = opposite direction of fingers (in neg quadrant - still x onto y)
• Only rotational/turning force will cause rotation:

  • Perpendicular component/force
  • Levers/mechanical advantage
  • Perpendicular to plane of movement greatest mechanical advantage
  • If off axis other components of force cause other things to happen
  • Forces not always perpendicular in limbs muscle force act in angle
  • Other components of force cause other to happen such as sliding, rotation along long axis, not helping us rotate
  • Hz force causing material to deform
  • Torque isolating component for rotation (need perpendicular component of the torque)