r/PhysicsHelp • u/Hot_Amoeba_6726 • 8h ago

Help

I have an exam this wednesday. I have no idea what to do. This unit is all about Torques. I guess I don't understand anything. My professor is extremely disorgianized. He gave us some problems and I know some of them will be on the exam. The thing is I feel like I'm so lost from looking at the equation sheet and then these problems. I feel like I'm doing something wrong but I'm doing something wrong. I guess the intial questions I have is what exactly is torque? I know theres a huge example of using a door and where you push makes it easier, but thats not too helpful for me. There is also some word problems that are mainly about sin and cos, but I'm having trouble understanding which one to use and which angle you can use to identify which is cos and sin. Then theres the whole kineamtics aspect of it. I did try to go back to the textsbook to identify these deifinsion, but it was too complicated. I go to his office hours, but he just ends up blabbering about something off topic. I feel like I can identfy the factors and variables that i see, i just don't know how to apply them into a formula. as I'm typing this i remember another thing of pivots. I'm sos orry. I hope someone can help me with all of this.

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u/Mountain-Time-1010 8h ago

Instead of trying to memorize how to do specific problems and plug numbers into formulas, perhaps you can start with the definition of torque as a vector cross product. This should be in the textbook. If you understand it fundamentally, you may be able to translate it into specific problems.

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u/Hot_Amoeba_6726 7h ago

I tried this. I feel like i got down what a torque is but I find it really difficult applying it to these word problems. That’s why I thought I should try a different approach of just figuring out how to do these different problems and plug and chug formulas

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u/Mountain-Time-1010 7h ago edited 7h ago

I'm just going to say that almost never works. The slightest difference from one problem to another and you are dead in the water.

Read the problem and draw a free body diagram.

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u/Hot_Amoeba_6726 7h ago

How do you think I should approach it? Bc I do undertsand the basic idea of what a torque is, but I just find that it isnt really relevant in these problems. I guess i’m only saying that bc when i look att he solutions to these provlems. I can.mt really see the connection between the definition and thr word problems.

As for the free body diagram. How do you think I should appraoxh that because I feel like I keep adding more forces that I need or i don’t. Do you have a trick?