imported>Patrick at 17:06, 31 July 2011

2011-07-31T17:06:00Z

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The diagram shows the gravitational force acting on the pendulum, the pivot (black dot) and the lever arm. 
[[image:Helena_Torque_Ex_2_Soln_A.png|TOP]] 

To solve this problem we first move the two vectors <math>\vec{r}</math> and <math>\vec{F}_G</math> so that they are placed "tail to tail", then we draw the x-axis parallel to the lever arm and we determine the angle between them: 
[[image:Helena_Torque_Ex_2_Soln_B.png|TOP]] 

Since we drew the vector of the force in the "fourth quadrant" we conclude that the direction of the torque is clockwise and therefore the torque is negative:

<math>\tau = -F_G r \sin{\theta} = -(2.5)(0.6)\sin{37^{\circ}} = 0.9 Nm</math>

Torque EX 2 - Revision history

imported>Patrick at 17:06, 31 July 2011