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The tensions are not "reactions" in the sense that they are not the 3rd law partners of the weights of the two masses, so they don't have to be equal to the weights. For the tension to be the same throughout the string, it must be 'light', i.e. massless. Because this equal tension can't possibly balance BOTH the two different weights, each mass will ...


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As the weight hanging off the table falls, it has some acceleration downwards. The force on the body is entirely due to gravity and is known. The string acts as a linkage between the hanging mass and the mass on the table. Really in this case, we have weights $m_1$ and $m_2$ being pulled by a force $m_1g$, which leads to the acceleration of the system being ...


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You cannot assume equal tension throughout if the pulley is not "massless" (assuming the rope does not slip over the pulley. Then adding a heavy load in one end will be carried by the string all the way up (Newton's 3rd law states that for all crosssections of the rope on this side, the forces must be equal). But if the pulley has inertia by having mass, ...


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Short answer. In your example, the rope can not be massless (otherwise its acceleration would be infinite), but if it has mass, then tension is different on each point of the rope. Therefore you have to assume there is an object connected to it. Depending on which side of the rope you assume the object is, you get tension 20N or 30N. This does not ...


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They will experience a different force. The rope and all parts of the rope are accelerating to the right at the same rate. If you slice the rope at $P_2$, there is a tension force that is accelerating that severed section to the right. That severed section has a mass that is less than the total mass of the rope, but the acceleration is the same, so the ...



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