This is one of the twelve images that make up "The Horse in Motion", copyright 1878 by Eadweard Muybridge and now available via Creative Commons license. In this image, the two front legs are rotating in opposite directions from our point of view one clockwise and one counter-clockwise around their respective shoulder joints. These images and those like them helped scientists understand the physics of gross-motor-motion for living things. In your first post, discuss the functional morphology or gait of a person or animal species as it relates to your data and observations. For example:How does a person change the moment of inertia of their arm when beginning to run as compared when they are walking? If you look at a picture of a running horse like the one shown below, can you tell which legs are rotating so that the foot moves toward the front of the horse and which are rotating in the opposite direction?If you watch the movement of a gymnast or diver, find/create a video clip that shows how their motion changes when they change their moment of inertia. This image is a famous photograph sequence capturing a horse in motion. It was taken by Eadweard Muybridge, an English photographer, known for his pioneering work in motion-picture projection. The image is a part of a series that were designed to study the movement of horses. **Description of the Image:**A horse is shown in mid-gallop, with all four of its legs off the ground. The rider is positioned forward, holding onto the reins. The background is minimal, focusing on the horse's dynamic motion. This freeze-frame is one of many taken in sequence that contributed to the understanding of animal locomotion, demonstrating that a horse’s hooves are all off the ground simultaneously during a specific moment in the gallop, which was not previously understood before this experiment.**Educational Focus:**- **Historical Significance**: This work provided early insights into motion study and laid the groundwork for the development of motion pictures.- **Scientific Impact**: Changed perceptions of animal locomotion and influenced future studies in biomechanics and locomotion.- **Technical Innovation**: Showcases photographic techniques that captured high-speed motion outside of traditional limitations. This sequence exemplifies the blend of art and science in capturing and analyzing movement, altering the way both artists and scientists viewed motion.

Walking Vs Running When a person walks, their arms are almost perpendicular to the body. Therefore, the biomechanical approach of a walking person can approach a thin rod. However, when the same person starts walking, his arms move away from the vertical plane of the body. This creates an additional moment of inertia. This can also be understood from the perspective of the parallel axis rotation theorem. Stretching the arm creates "additional" inertia by separating the center of gravity of the arm from the center of gravity of the slender body.The Horse motion The motion of the horse can be categorized into various types such as gallop, pace, canter etc. However, as far as the image shown in the question is concerned, the limbs on one side (left or right) tend to move in the same sense. This means, that limbs in the right half move together while the limbs in the other, left half also move together, in sync. The difference arises when the two halves moves either together or in exact opposite sense of each other. In the image shown in the question, the right leg (as viewed by the horse-rider) rotates so that the left leg moves forward. When the right leg is grounded, the left leg rotates, while in air so that the right leg moves forward. This scheme is the driving biomechanics of a horse in motionBiomechanics of gymnasts/divers: Gymnasts or divers utilize the moment of inertia of their bodies in order to change their motion. In all this process, the angular momentum of the gymnast/diver remains fairly constant (since no external force is being applied on him/her). Angular Momentum = Moment of Inertia x Angular Velocity Angular Momentum = constant When a gymnast spreads out his arms, the moment of inertia increases (as above in walking vs running). Thus, for the angular momentum to remain constant, the angular velocity decreases and the gymnast/diver cannot spin and performs longitudinally or a nosedive. When the arms are folded, moment of inertia decreases and thus the angular velocity increases in order to conserve angular momentum. Thus the motion of the gymnast or diver changes and thus they can perform in full circles or dive while spinning.