Question

BPK201

In the figure to the right, ? is "

the force generated by the tendon that flexes the distal

finger joint. ? is the external #$"

force acting on the finger tip.
The position vectors of the point
of force application of these two
forces relative to the joint center
of rotation, c, is illustrated
within the dotted box. Calculate
the effective mechanical
advantage of the tendon relative
to the external force. Is this mechanical advantage better suited for amplifying muscle force or speed? (6 pts)

In the figure to the right, F, is the force generated by the tendon that flexes the distal finger joint. Fext is the external force acting on the finger tip. The position vectors of the point of force application of these two ·y F.(0.1N) forces relative to the joint center of rotation, c, is illustrated within the dotted box. Calculate the effective mechanical advantage of the tendon relative to the external force. Is this mechanical advantage better suited for amplifying muscle force or speed? (6 pts) 5. ,-(SN,IN) ie te

Answer 1

The moments generated by tendon is counter clockwise (positive) and the moment generated by the external force is clockwise (negative). We can calculate the moment by taking the cross product between the Force and position vectors.

The moment generated by the tendon is given by,

The moments generated by tendon is counter clockwise (positive) and the moment generated by the external force is clockwise (negative). We can calculate the moment by taking the cross product between the Force and position vectors. The moment generated by the tendon is given by, M_1 = r vector times F vector = (-3 j^) times (5 j^+ 1 j^) = 15 k^The moment generated by the external force is given by M_2 = r vector times F vector = (- 15 i^- 6 j^) times (1 j^) = -15 k^This means that this tendon force is enough to counter act the external force. Hence the Mechanical Advantage is given by, (We are considering the magnitude of the forces) MA = F_ext/F_tendon = 1/squareroot 5^2 + 1^2 = 0.2 Since mechanical advantage is less than 1, this configuration is better suited for amplifying the speed.

The moment generated by the external force is given by,

This means that this tendon force is enough to counter act the external force. Hence the Mechanical Advantage is given by,

(We are considering the magnitude of the forces)

Since mechanical advantage is less than 1, this configuration is better suited for amplifying the speed.