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.

A tractor is speeding up at 3 m/s/s while pulling a 1,011 kg sled with a rope at an angle of 23 degrees. The coefficient of kinetic friction between the sled and ground is 0.3. What is the tension (Newtons) in the rope? (g=9.8 m/s?)

It’s an arm day at the gym and all the free weights and machines are taken. You don’t have much time to squeeze in your workout before your next class. Desperate to get your reps in, you see a pile of Therabands (the giant rubber bands used for physical therapy). The bands are 100 mm wide and 1.5 mm thick. You sit down to do some bicep curls with the Theraband tied to rack 60 cm away from your hand and your hand is 80 cm from the floor. However, a single length of the Theraband is too easy to curl, so you end up wrapping it around your hand twice (i.e. you are stretching 4 lengths of Theraband when you do your reps). Your hand starts out 60 cm from the Theraband anchor point before your do your bicep curl (i.e. no stress on the band, band has no slack). You contract your bicep until your forearm is parallel with the floor and hand in the position below and hold static equilibrium. From previous obsessing over your personal biomechanics, you know the following: your arm and hand weigh 2…

Please answer the questions in red.