Help finding radius for the torque

In summary, the conversation discusses finding the radius for the torque of a cable, with one person initially struggling to use trigonometry to solve for the radius, but the other person clarifies that the radius is simply equal to the distance from the pivot point to the point where the force is acting on the beam. They also mention using the sine function to relate the side opposite the angle to the hypotenuse in a right triangle.
  • #1
PhizKid
477
1

Homework Statement


PnLnY.png



Homework Equations


Torque = Force * radius * sin(angle)


The Attempt at a Solution



wWVKm.png


I am trying to find the radius for the torque of the cable, but I can't seem to use any trig to solve for that side in terms of L.
 
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  • #2
The radius is L,
you do not need any trigonometry.
remember, radius (when referring to torque) is defined as the distance from the pivot point to the point that the force is acting on - in other words - L.
 
  • #3
The pivot point to the point that the force is acting on is marked in my diagram by 'R'. I don't see how R = L
 
  • #4
The wire is pulling on the beam with a tension, this is the force in question. The point that you have marked as the point that the force is acting upon is on the wire itself. In order to cause a torque on the beam the force must be acting on the beam itself, not the wire.
 
  • #5
I don't understand what you are saying. The force of the Tension is acting on the beam. The axis of rotation is the hinge. So, we need the distance from the Tension to the axis of rotation. To do that, we use the perpendicular distance created from the axis of rotation to the Tension. Isn't that what we want?
 
  • #6
You have a right triangle where L is the hypotenuse and R is the side opposite the 30-degree angle. What trig function relates side opposite and hypotenuse?
 
  • #7
Ah, I see the sine function now. Thanks
 

1. How do I calculate the radius for torque?

To calculate the radius for torque, you will need to know the force applied and the lever arm distance. Then, use the formula: torque = force x lever arm distance. Rearrange the formula to solve for radius: radius = torque / force.

2. What if I don't know the force applied?

If you do not know the force applied, you can use the formula: torque = force x radius. Rearrange the formula to solve for radius: radius = torque / force. You will need to have the torque value and an estimate of the force applied in order to calculate the radius.

3. Can I find the radius for torque without knowing the lever arm distance?

No, you will need to know the lever arm distance in order to calculate the radius for torque. The lever arm distance is the perpendicular distance from the axis of rotation to the point where the force is being applied.

4. How do I measure the lever arm distance?

The lever arm distance can be measured using a ruler or tape measure. It is the shortest distance from the axis of rotation to the point where the force is being applied. It is important to measure from the point of rotation, not from the edge of the object.

5. What units should I use for radius and torque?

The units for radius are typically in meters (m) or centimeters (cm). The units for torque are typically in Newton-meters (Nm) or foot-pounds (ft-lb). It is important to use consistent units when calculating torque and radius to ensure accurate results.

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