Late reply, but try plugging in some numbers. I believe he is right. If you want to say that the smaller one rotates faster than the bigger one, then you really do want to do 4 * big = small. If you set big = 1 rotation, then the small = 4 rotation. If you did big = 4 * small, then you'd be saying 1 rotation of the small one equals 4 rotations of the big one, which just doesn't make sense.
Because the shaft runs a much longer length, and deforms a much greater amount under the same torsional load. The gear would have its own elasticity as well, but it is considered negligible in this problem. Suppose the gear is either mad out of a significantly stiffer material, or the diameter of the gear is so large that its own deformation is negligible.
I think there is a mistake In the free body diagram, If we had one force on it that force would take it to somewhere, why didn't you add another force to balance it.
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I have exam in two days , your videos helped me a lot thank you professor :)
Wonderful solids lessons!! really taking the time to explain the problems along with a good sense of humor :))
If gear E (the big one) rotates 2 times then gear F (The small one) rotates 4 time. why did you put 2 with the phi E? shouldn't it be with phi F? 4:57
Late reply, but try plugging in some numbers. I believe he is right.
If you want to say that the smaller one rotates faster than the bigger one, then you really do want to do 4 * big = small. If you set big = 1 rotation, then the small = 4 rotation.
If you did big = 4 * small, then you'd be saying 1 rotation of the small one equals 4 rotations of the big one, which just doesn't make sense.
You're a god Jeff, thanks for your videos!
when calculating for the angle of twist, why is the radius used in calculating polar moment of inertia from the rod and not the gear?
Because the shaft runs a much longer length, and deforms a much greater amount under the same torsional load.
The gear would have its own elasticity as well, but it is considered negligible in this problem. Suppose the gear is either mad out of a significantly stiffer material, or the diameter of the gear is so large that its own deformation is negligible.
@@carultch thank you very much. Your videos are incredibly helpful and are saving me big time.
I love you bro
lowkey took me a solid 5 min to figure out it was diameter last video lmao
I think there is a mistake In the free body diagram, If we had one force on it that force would take it to somewhere, why didn't you add another force to balance it.
You are correct, there would be a reaction force at the wall as well but that force would no create a torque so it is irrelevant in this example.
Best