Biomechanics (BE 202)
Homework #2 (100/100)
Due date: 2/16/2016
1
1. (20pts) Consider a person’s arm shown below. When a vertical (y-directional) force is applied to the hand
(H), estimate the moment at the elbow (E) and shoulder (S) produced by this force.
(Here, xy: frontal plane, yz: sagittal plane, and xz: transverse plane)
2. (30pts) As illustrated below, force F is applied to a block on a point P. The application point of the force, P,
can be any point on the edge AB.
(a) (15pts) Find the moment vector at O produced by the force F.
(b) (5pts) Find the location of the point P (i.e., determine x value) where the moment about x axis (Mx) is
minimized.
(c) (5pts) Find the location of the point P where the moment about y axis (My) is minimized.
(d) (5pts) Find the location of the point P where the moment about z axis (Mz) is minimized.
Biomechanics (BE 202)
Homework #2 (100/100)
Due date: 2/16/2016
2
3. (20pts) Determine the net moment about the hip joint (H) produced by the weight attached to the ankle (A).
4. (30pts) A person is pulling a weight as shown below. His shoulder joint is not moving, but his elbow joint is
free to rotate;
(a) (15pts) Calculate the moment at the elbow joint (E) produced by the weight. In other words, represent the
elbow moment ME as a function of the elbow flexion angle ?.
(b) (15pts) Find the elbow angle ?max where the magnitude of the moment about the elbow joint (??????) is
maximized.

Homework #2 (100/100)
Due date: 2/16/2016
1
1. (20pts) Consider a person’s arm shown below. When a vertical (y-directional) force is applied to the hand
(H), estimate the moment at the elbow (E) and shoulder (S) produced by this force.
(Here, xy: frontal plane, yz: sagittal plane, and xz: transverse plane)
2. (30pts) As illustrated below, force F is applied to a block on a point P. The application point of the force, P,
can be any point on the edge AB.
(a) (15pts) Find the moment vector at O produced by the force F.
(b) (5pts) Find the location of the point P (i.e., determine x value) where the moment about x axis (Mx) is
minimized.
(c) (5pts) Find the location of the point P where the moment about y axis (My) is minimized.
(d) (5pts) Find the location of the point P where the moment about z axis (Mz) is minimized.
Biomechanics (BE 202)
Homework #2 (100/100)
Due date: 2/16/2016
2
3. (20pts) Determine the net moment about the hip joint (H) produced by the weight attached to the ankle (A).
4. (30pts) A person is pulling a weight as shown below. His shoulder joint is not moving, but his elbow joint is
free to rotate;
(a) (15pts) Calculate the moment at the elbow joint (E) produced by the weight. In other words, represent the
elbow moment ME as a function of the elbow flexion angle ?.
(b) (15pts) Find the elbow angle ?max where the magnitude of the moment about the elbow joint (??????) is
maximized.

Homework #2 (100/100)
Due date: 2/16/2016
1
1. (20pts) Consider a person’s arm shown below. When a vertical (y-directional) force is applied to the hand
(H), estimate the moment at the elbow (E) and shoulder (S) produced by this force.
(Here, xy: frontal plane, yz: sagittal plane, and xz: transverse plane)
2. (30pts) As illustrated below, force F is applied to a block on a point P. The application point of the force, P,
can be any point on the edge AB.
(a) (15pts) Find the moment vector at O produced by the force F.
(b) (5pts) Find the location of the point P (i.e., determine x value) where the moment about x axis (Mx) is
minimized.
(c) (5pts) Find the location of the point P where the moment about y axis (My) is minimized.
(d) (5pts) Find the location of the point P where the moment about z axis (Mz) is minimized.
Biomechanics (BE 202)
Homework #2 (100/100)
Due date: 2/16/2016
2
3. (20pts) Determine the net moment about the hip joint (H) produced by the weight attached to the ankle (A).
4. (30pts) A person is pulling a weight as shown below. His shoulder joint is not moving, but his elbow joint is
free to rotate;
(a) (15pts) Calculate the moment at the elbow joint (E) produced by the weight. In other words, represent the
elbow moment ME as a function of the elbow flexion angle ?.
(b) (15pts) Find the elbow angle ?max where the magnitude of the moment about the elbow joint (??????) is
maximized.