Calculating Torque for F1: 50N at d1-d3

[cdornz]

Homework Statement

What is the torque about a?
F1 = 50N (located between d2 and d3)
d1 = 9cm
d2 = 10cm
d3 = 8 cm

Homework Equations

T=(F)(Lever Arm)

The Attempt at a Solution

I'm extremely rusty with this material, but I realize I can't quite use the torque equation since the force isn't at the center of gravity. Any help would be appreciated.

 

[Doc Al]

Please provide a complete description of the problem. Where's a? What are d1, d2, and d3? A diagram would help.

 

[cdornz]

This is what I worked it out to be, just want to make sure I'm doing it right.

 

[Doc Al]

This is what I worked it out to be, just want to make sure I'm doing it right.

Looks good to me.

 

[cdornz]

thank you! and just one more question - slightly related to torque equations in general. When the force is exerted in that direction, it is considered a moment and therefore equal to 0 correct? Because no actual force is exerted on that line? So I would then think that the torque about p would be zero.

 

[Doc Al]

thank you! and just one more question - slightly related to torque equations in general. When the force is exerted in that direction, it is considered a moment and therefore equal to 0 correct? Because no actual force is exerted on that line? So I would then think that the torque about p would be zero.

The lever arm is the perpendicular distance from the pivot point to the line of action of the force. In this case, the line of action of the force passes through p, so the lever arm and thus the torque is zero. Force is exerted, of course, but no torque.