The discussion revolves around applying the principle of conservation of string in a problem involving a sub-pulley system. Participants express uncertainty about how to approach the problem, particularly in relation to the symmetry of the sub-pulley and the relationships between the masses involved.
The discussion is ongoing, with participants offering insights into the relationships between the masses and the implications of conservation of string. Some guidance has been provided regarding the setup of equations, but there is no explicit consensus on the approach yet.
There is mention of the original poster's difficulty with the problem due to the presence of a sub-pulley, which is noted as a point of confusion. The discussion also references specific equations and relationships that participants are considering, indicating a focus on mathematical reasoning.
The sub-pulley is symmetric, correct? That is, there is no difference between its right and left hand sides? They are mirror images of each other?mancity said:
I take the masses as unknown.jbriggs444 said:
Write equations relating string (section) lengths to heights of masses, throwing in constants as necessary. Differentiate twice.mancity said:
'Conservation of string' is an unusual way to state that the length of the string is constant. So when you set up a set of equations for your exercise, one of them is a relationship betweenmancity said:
Relative to the bottom pulley, the average acceleration of the bottom two masses is zero. The acceleration of the upper mass is minus the acceleration of the bottom pulley.mancity said:
My impression is that the OP has been instructed to use conservation of string length to obtain the result. That suggests to me applying your framework to positions and then differentiating.Chestermiller said:
