Torque of fish pulling on pole

by Patrick Ford
Was this helpful ?
Hey, guys, let's check out this example where we asked to find the torque produced by a force with two different angles here. So here we have a fish catching your bait. Um, your fishing pole is at an angle of 50 degrees above the X axis. So let's say you are like this holding onto your fishing pole that has its 3 m long 2 kg, and it makes an angle off 50. Right there. We wanna calculate the torque that's produced on your fishing pole about an axis of rotation on your hands. In other words, think that the fishing pole rotates about the hands right there. So that's the axis of rotation access right here. If the fish pulls on it with 40 Newton's, that's a force directed at 20 degrees below the X axis. So the line is here you're pulling from here. The fish is pulling at an angle. Direct that 20 degrees below the X axis. So here's a positive X axes 20 degrees below the X axis. Looks like this. So I'm gonna negative 20 over here, and the fish is pulling with a force of 40 Nuyens and we want to know How much does this force How much of a torque does this force produced on this axis? Right here. So we're gonna use my right. The torque equation. Torque equals f r sine of fada. I remember the steps. The first thing we're gonna do is writes the draw, our vector. Then we're gonna figure out what Data is, and then we're gonna plug it into the equation. Okay, So what is our our vector are vector is an arrow. It's a vector from the axis of rotation to the point where the force happens where the force is applied on the object. So the acts of rotations here, the force pulls right there were drawn arrow. This is our our vector. Okay, Now, the length of the our vector is 3 m, So that's what I'm gonna put here. So 40 three times three sign of theta now drawing the our vector is important. Actually, not so much so that you can figure out how long it is because you could have just looked at this. Poland said the polls 3 m long. That's the answer. What's really important about drawing the our vector is so that you can figure out what angle to use, which is the hardest part. Okay, you've got to make sure you're using the right angle. So here, should we use 50? Should we use 20 issue? We use negative 20. It actually turns out that in this problem, it's none of these options. It's a it's a different angle. It's a combination of the two. I want to remind you that data is the angle between f and R and to figure out which angle goes between them. The technique I like to use is to try to get F and are to be pointing from the same common point something like this. And then it's just a matter of finding this angle right here. And to do this, I'm going to shift f around or shift are around so that they start from the same point. So what I'm gonna do here is I'm going to push. I'm gonna shift my are up so that they both start from this point. Okay, so let me draw this again. I have 50. Draw this a little lower. I have 50 over here, and then I have 20 here. Okay. What I'm gonna do is I'm gonna get the our vector and push it over here so that I have are and f And then the angle I need is the angle between these two guys. Okay, Now you see here how There is a 50 between the our and the X axes. Right? Right here. There's a 50 between our and the X axis. So this angle here between our and the X axis is also a 50. So this 50 gets transferred over here and now, I hope you see that the total angle between R and F is actually 70 degrees. So you're supposed to add up those two guys. Okay. So this the entire purpose of this question was to look into how to solve questions with non trivial, um, fatal values, angle values and how to figure out the correct angle to use. Okay. To multiply all of this, you get 113 Newton's, um, meter, and that's your final answer. Cool. That's it for this one. Let me know if you have any questions. Let's keep going