How Is Torque Calculated on a Triangular Plate with Pivoted Forces?

In summary, a light triangular plate OAB is pivoted about a vertical axis through point O and has 3 forces acting on it: F1 = 7 N, F2 = 3 N, and F3 = 8 N. The sum of the torques about the vertical axis through point O is closest to 0.30 N*m, with F2 producing a positive torque of 2.4 N*m and F1 producing a negative torque of 2.1 N*m. The angle between F1 and the dotted line is 30 degrees and the angle between the dotted line and F3 is 45 degrees. The torque produced by F3 is 0 m*N since r = 0 m, therefore only
  • #1
Soaring Crane
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A light triangular plate OAB is in a horizontal plane. The 3 forces, F1 = 7 N, F2 = 3 N, F3 = 8 B, act on the plate, which is pivoted about a vertical axes through point O. Consider the counterclockwise sense as positive. The sum of the torques about the vertical axis through point O, acting on the plate due to forces F1, F2, and F3, is closest to:

a. 0.30 N*m-----------b. 1.2 N*m---------c. –0.30 N*m------d. –1.2 N*m-------e. zero

In the attachment, please note that the angle between F1 and the dotted line is 30 degrees. The angle between the dotted line and F3 is 45 degrees.
Angle 1 = 30 degrees
Angle 3 = 45 degrees

Hypotenuse = 1.0 m

If you cannot see the attachment, please tell me.

Since the plate is rotated around point O,

The torque where F3 acts is 0 m*N since r = 0 m??

Therefore, only forces 1 and 2 are left.

Is Force 2 counterclockwise, which makes it positive? Torque 2 = F*r*sin theta = 3N*0.8 m*sin 90 = +2.4 m*N??

Is Force 1 clockwise, which makes it negative? Torque 1 = F*r*sin theta = 7N*sin 90*0.6 m = -2.1 m*N?

Sum of torques = 2.4 m*N – 2.1 m*N = 0.30 m*N??

Thanks.
 

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  • #2
Unfortunately, I cannot see the attachment, but it is possibly due to my computer [:grumpy:]. But yes, if the force vector intersects with the axis, the torque produced by that force must equal zero.
 
  • #3
I tried saving it as a Word document. Hopefully, it is accessible now.
 

Attachments

  • Diagramplate.doc
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  • #4
Are my signs for the torque correct?

Thanks again.
 
  • #5
Yes, your signs are correct.
 

What is torque and how is it calculated?

Torque is a measure of the force that causes an object to rotate around an axis. It is calculated by multiplying the force applied to an object by the distance from the axis of rotation to the point where the force is applied.

What is the relationship between torque and force?

Torque and force are directly proportional to each other. This means that as the force applied to an object increases, the torque also increases.

How does the sum of torque and forces affect an object's motion?

The sum of torque and forces on an object determines its rotational motion. If the sum of torque and forces is zero, the object will remain at rest or in a state of constant rotation. If the sum is not zero, the object will experience acceleration or deceleration in its rotation.

What is the difference between positive and negative torque?

Positive torque occurs when the force applied causes an object to rotate in a counterclockwise direction. Negative torque occurs when the force applied causes an object to rotate in a clockwise direction. The direction of rotation is based on the right-hand rule, where the fingers curl in the direction of rotation and the thumb points towards the axis of rotation.

How is torque and force used in real-world applications?

Torque and force are used in many real-world applications, such as in engines, bicycles, and torque wrenches. In engines, torque is used to convert the linear motion of the pistons into rotational motion to power the vehicle. In bicycles, torque is used to transfer the energy from the rider's legs to the wheels. Torque wrenches are used to apply a specific torque to bolts and screws to ensure they are tightened to the correct amount.

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