What Is the Correct Way to Calculate Net Torque?

[trajan22]

Calculate the net torque about point O for the two forces applied as in the figure View Figure . The rod and both forces are in the plane of the page. Take positive torques to be counterclockwise.

A image is here to show the problem

What i did
12Nsin(30)*(2m)-(8N*3m)
or if you like this better
F2sin(theta)*d-(F1*d)
however this isn't working should i not be neglecting the y component of F2 or do i have the angle wrong...i am confused any help is appreciated.

it appears my image is taking forever to get approval so i will try and explain the problem.
there is a rod where the axis of rotation is on the left end of it
2 meters from this axis is a force going up and to the left, at a 30 degree angle. with a magnitude of 12N (F2)
Another force is a total of 5 meters from the point of rotation and is vertical with a magnitude of 8N (F1)
nevermind i turned out to be right...i just made a dumb error.

 

[sarine4512]

i'm confused as to how to come up with an answer, trajan22. did you happen to get -12 ..clockwise for the answer??

 

[thomate1]

I would first like to commend you for attempting to solve this problem on your own. Calculating net torque can be a challenging task, but with some practice, it can become easier.

Based on the information provided, it seems that you have correctly identified the two forces (F1 and F2) and their respective distances from the point of rotation (d = 2m and d = 5m). However, it appears that you have made a mistake in your calculation.

To calculate net torque, we need to take into account both the magnitude and direction of the forces. The direction of the force F2 is given as 30 degrees counterclockwise from the horizontal, which means it has a positive torque. The force F1, being vertical, has no torque since it acts directly on the point of rotation.

Therefore, the correct calculation for net torque would be:

Net torque = (F2 * sin(30) * d) + (F1 * 0 * d)

= (12N * sin(30) * 2m) + (8N * 0 * 5m)

= 12N * 0.5 * 2m + 0

= 12N * 1m

= 12 Nm counterclockwise.

I hope this helps clarify your confusion. Remember to always pay attention to the direction of the forces when calculating net torque. Keep practicing and good luck!