Dynamic Analysis of Motion - Biomechanics

AI Thread Summary
The discussion revolves around a physics homework problem involving the dynamics of a leg under specific forces. A horizontal ground reaction force of 200N and a vertical force of 1200N are applied, with the leg experiencing accelerations of -4m/s² in the x-direction and 8m/s² in the y-direction. Participants suggest drawing a free body diagram to visualize the forces acting on the leg, including the unknown forces at the hip. The equation F=MA is emphasized for calculating the total force across the hip, although the mass of the leg is needed for precise calculations. Overall, the conversation focuses on guiding the student through the problem-solving process.
kreuzberg
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Homework Statement


A leg has a horizontal propulsive ground reaction force 200N and vertical ground reaction foce of 1200N applied to it. Draw a free body diagram. The leg has an acceleration of -4m/s2 in the x direction and 8m/s2 in the y direction. What are the horizontal + vertical components of the force acting across the hip? What is the total force across the hip?


Homework Equations


F=MA


The Attempt at a Solution


Hi, I have read the community guidelines specifying that you need to show your own attempt. I wish I could but I really have no idea how to do this question. Could someone guide me with how to approach this question? All help would be appreciated. :)
 
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welcome to pf!

hi kreuzberg! welcome to pf! :smile:

treat the leg as a separate body

draw a free body diagram for it …

there will be the two given forces at the bottom of the leg (the ground), and two unknown forces (cal them H and V) at the top (the hip)

(technically, there's also the weight of the leg itself, acting vertically at the middle of the leg, but i think that's so small that you're expected to ignore it :wink:)

apply F = ma (i think you'll need to know the mass of the leg) …

what do you get? :smile:​
 

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