Ans: 1. τbiceps = +(Positive)2. τforearm = -(Negative)3. τball = -(Negative)Explanation:The figure is attached down below.
1. T<span>orque about the elbow caused by the biceps, τbiceps:
Since Torque =
r x
F (where
r and
F are the vectors)
</span>Where
r is the vector from elbow to the biceps.
<span>
We can see in the figure that
F(biceps) is in
upward direction, and by applying the
right hand rule from
r to F, we get the
counterclockwise direction. The torque in counterclockwise direction is
positive(+). Therefore, the sign would be
+.
2. </span>Torque about the the weight of the forearm, τforearm:
Since Torque =
r x
F (where
r and
F are the vectors)
Where
r is the vector from elbow to the forearm.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that
W(
forearm) is in
downward direction, and by applying the
right hand rule from
r to F, we get the
clockwise direction. The torque in clockwise direction is
negative(-). Therefore, the sign would be
-.
3. Torque about the the weight of the ball, τball:
Since Torque =
r x
F (where
r and
F are the vectors)
Where
r is the vector from elbow to the ball.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that
W(
ball) is in
downward direction, and by applying the
right hand rule from
r to F, we get the
clockwise direction. The torque in clockwise direction is
negative(-). Therefore, the sign would be
-.
