The discussion revolves around the mechanics of lifting a bucket and the application of torque, specifically questioning whether the elbow serves as the point of application of force in this context. The scope includes conceptual understanding of levers and torque in human biomechanics.
Participants express differing views on the point of application of force, with some asserting it is at the biceps insertion on the radius, while others initially consider the elbow or shoulder. The discussion remains unresolved regarding the exact nature of the force application in this context.
The discussion does not clarify the assumptions regarding the definitions of torque and force application points, nor does it resolve the mathematical implications of the lever systems involved.
Normally when you pick up a bucket you apply a force to the bucket (through the CoM - Centre of Mass - of the bucket), but no torque about the CoM.David lopez said:if i pick up a bucket i apply torque to the bucket. my shoulder is the fulcrum. is my elbow the point of application of force? just trying to understand the physics?
If you lift a bucket, there are at least two levers in operation.David lopez said:if i pick up a bucket i apply torque to the bucket. my shoulder is the fulcrum. is my elbow the point of application of force? just trying to understand the physics?
so where would the application of force be?jbriggs444 said:If you lift a bucket, there are at least two levers in operation.
Let us suppose that you have grabbed the bucket by its bail handle. The bucket is currently on a table in front of you. Your upper arm is near vertical and your lower arm is extended in front of you to the bucket.
You lift the bucket. Your elbow joint is acting as a fulcrum. Your biceps muscle is contracting, putting a large force on the tendon that attaches it to the radius bone in your forearm. Your hand rises as a result and the bail handle provides the load against which your hand lifts.
Considering the lower arm only, that makes this a class 3 lever.
At the point where the biceps tendon attaches to the radius.David lopez said:so where would the application of force be?
No. Not at the shoulder. Not near the shoulder. At the point where the biceps meets the radius. The point labeled "Insertion of the Biceps Bracchi". We are considering the lower arm as the lever.David lopez said:so at the shoulder or near the shoulder?