Torque Calculation & Error Question

In summary, the conversation is about finding the point of equilibrium for a horizontally-projected rod in an experiment. The givens include the mass and length of the rod, as well as the weights attached to the rod and string, and the distance from the hinge. The two scenarios involve changing the angles of the rod and the pulling string. The equations used are for calculating torque and moment of inertia. The person has computed the torques for the weights and string, but is unsure how to factor in the rod's own torque. They are seeking advice on how to do so.
  • #1
revo8778
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Homework Statement



This is a problem from an experiment wherein one must find the point of equilibrium for a horizontally-projected rod that hinges from it's left endpoint. I have already performed the experiment, and now have to calculate the error by comparing the torques pulling down on the rod to the torque pulling up via a string looped around a pulley to a hanging mass. This must be done in two specific scenarios.

Givens:

Mass, length of rod: .1131kg, .577m
W1 weight attached to rod, dist. from hinge: .1177kg, .38m
W2 weight attached to rod, dist. from hinge: .2502kg, .529m
W3 weight attached to string: .2502kg
String Mount's dist from hinge: .43m

The two scenarios change the angles of the rod to the horizontal, and the pulling string to the rod.

First scenario: Angle to horizontal = 0 degrees, Angle of string to rod = 55 degrees.
Second scenario: : Angle to horizontal = 47 degrees, Angle of string to rod = 90 degrees.

Homework Equations



I = (mr^2)/3
T = Fr(sin [theta]) = I[alpha]

The Attempt at a Solution



I have computed all of the torques that I can; they are listed below. My problem is that I don't know how to factor in the instrinsic torque of the rod itself.

Trqe of W1: .438
Trqe of W2: 1.297

Gravity is 9.8m/s^2
 
Last edited:
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  • #2
String Tension of Scenario 1: 9.8*cos(55) = 7.14NTrqe of String in SC1: 0.893String Tension of SC2: 9.8*cos(90) = 0NTrqe of String in SC2: 0I think I need to find the torque due to the rod's own rotation, but I am not sure. If anybody could provide a hint as to how to factor that into my calculations, I would be very grateful.Thanks!
 

What is torque?

Torque is a measure of the force that causes an object to rotate around an axis. It is typically represented by the symbol "τ" and 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.

How do you calculate torque?

To calculate torque, you need to know the force applied to an object and the distance from the axis of rotation to the point where the force is applied. The formula for torque is τ = F x d, where τ is torque, F is the force applied, and d is the distance from the axis of rotation to the point where the force is applied.

What are the units of torque?

The SI unit for torque is Newton-meters (N·m). However, torque can also be expressed in other units such as foot-pounds (ft·lb) or inch-pounds (in·lb).

How do you account for errors in torque calculations?

There are several sources of error in torque calculations, such as incorrect measurement of force or distance, friction, and human error. To account for these errors, it is important to use precise and accurate measurements, reduce friction as much as possible, and double-check calculations for any potential mistakes.

What are some real-world applications of torque calculation?

Torque calculation is used in many industries and fields, such as engineering, physics, and automotive. It is used to design and analyze machines and structures, determine the amount of power needed for certain tasks, and understand the forces involved in rotational motion. It is also used in everyday tasks like tightening bolts and nuts, and in sports such as golf and baseball to improve performance and prevent injury.

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