How Do You Calculate Torque in a Fishing Pole Scenario?

[APool555]

We just started torque and our teacher gave us some problems but we didn't do any examples. I have no idea where to start. Thanks for your help.

The fishing pole in Figure P10.30(i drew a picture of it) makes an angle of 20 degrees with the horizontal. What is the torque exerted by the fish about an axis perpendicular to the page and passing through the fishers hand?

 

[FredGarvin]

You need to find the component of the force exerted by the fish (the 100 N) that is perpendicular to the fishing pole. To do that, you have to look at the end of the pole and the two angles you are given. You will have your 100N force as the hypotenuse of a right triangle and you need to find the angle it makes with the pole.

20° + 37° = 57°. That's not quite 90°. That means that the angle that is made by the force vector is 90-57 = 33°.

Now that you know the angle that the force is at in relation to the pole, you have to get the component that is perpendicular, or in this case, the adjacent side of the triangle. The length of the adjacent side is going to be 100 N* cos 33° = 83.9 N.

Now all you have to do is calculate the torque by taking the force and the distance to the hand, which in this case is T = (83.9N)*(2.0m) = 167.8 N*m.

 

[thepatientmental]

Hi there,

I understand that torque problems can be confusing at first, but with some practice and understanding of the concept, you will be able to solve them easily. Let me walk you through the steps to solve this particular problem.

First, let's define torque. Torque is the measure of a force's ability to rotate an object around an axis or pivot point. It is calculated by multiplying the force applied by the distance from the axis of rotation. In this case, the force is the weight of the fish, and the distance is the length of the fishing pole.

Next, we need to determine the direction of the torque. Since the question specifies an axis perpendicular to the page, we know that the torque will be either clockwise or counterclockwise. To determine the direction, we need to use the right-hand rule. If you point your fingers in the direction of the force (towards the fish), your thumb will point in the direction of the torque. In this case, the torque will be counterclockwise.

Now, we can use the formula for torque: torque = force x distance. The force in this case is the weight of the fish, which we can find using the formula weight = mass x gravity. The mass of the fish is not given, so let's assume it to be 1 kg for simplicity. The gravity on Earth is approximately 9.8 m/s^2. Therefore, the weight of the fish is 1 kg x 9.8 m/s^2 = 9.8 N.

The distance in this case is the length of the fishing pole. Let's assume it to be 1 meter. Therefore, the torque exerted by the fish is 9.8 N x 1 m = 9.8 Nm.

I hope this explanation helps you understand how to approach torque problems. Remember to always draw a diagram and use the correct units in your calculations. With practice, you will become more comfortable with solving these types of problems. Good luck!