In our last lab we found that the “turning effect” depends on the force and the lever arm.
r2
r1

F2  m2 g

F1  m1g
Clockwise
Turning Effect
Counterclockwise
Turning Effect
Turning Effect  r F
Where
tau
Torque    the turning effect
r= Lever arm - perpendicular distance from the axis
of rotation to the point of application of
the force.
  r F
Torque    the turning effect
  r F
Where r = perpendicular distance from the axis
of rotation to the point of application
of the force.
Units : N m
Torque is a vector!
Torques that would result in
Counterclockwise rotation = +
Torques that would result in
Clockwise rotation = -
Right Hand Rule – curl the fingers of your right hand
in the direction of rotation. The
vector is in the direction of your
outstretched thumb.
The object rotates around the torque vector.
Torque    the turning effect
  r F
Where r = perpendicular distance from the axis
of rotation to the point of application
of the force.
In all cases thus far, the force acted perpendicularly to the distance from the axis of
rotation.
Later, we will consider how much torque is applied when the force and
the distance are not perpendicular.