Calculating Net Torque for an Inclined Wheel: A Problem in Applied Physics

[Erenjaeger]

Homework Statement

Find the net torque on the wheel in the figure below about the axle through O, taking a = 13.0 cm and b = 31.0 cm. (Assume that the positive direction is counterclockwise.)
pic: https://fbcdn-sphotos-c-a.akamaihd...._=1470130918_26fa32f17821823200ba75439cef0a52
[/B]

Homework Equations

τ=f⋅d[/B]

The Attempt at a Solution

just sum all for torque, I thought you could just go
τ₁=9.0N ⋅ 0.31m = 2.79 n⋅m
τ₂=10.0N⋅0.31 = 3.1 N⋅ m
but the torque component with the angle shown, I calculated it the same and then summed all the values of torque together, and it said it was wrong, so I am assuming that you have to add something like a cosine or sine into that component because it isn't in a horizontal or vertical direction but 150° below the horizontal (positive x axis) any tips on how to solve this,?

 

[Orodruin]

I calculated it the same

This does not actually show us what you did. Please specify the values you put in and the result you got.

 

[Erenjaeger]

This does not actually show us what you did. Please specify the values you put in and the result you got.

i don't understand how it doesn't show what i did? i completely explained what i did. the two net torques i gave how i calculated them and got 2.79 N.m and 3.1 N.m and said i did the same for the third component so obviously following that i went 12.0N x 0.13m which gave me 1.56 N.m, then i said i summed all my values for torque together, thus 2.79+3.1+1.56 which equals 7.45N.m but that value was incorrect. Does that explain it anymore or was there something else you need to know??

 

[haruspex]

i completely explained what i did.

No, you left out this initially:

following that i went 12.0N x 0.13m

2.79+3.1+1.56

Think about directions (more precisely, "sense").

 

[Orodruin]

i don't understand how it doesn't show what i did? i completely explained what i did.

No you did not, you left out a crucial part, your computation of the last contribution and the final result. Haruspex has already given you a good hint. Try to interpret it and ask again if you still cannot work it out.