What is the mass of the ruler moments? (Answer: 127.04g)

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Homework Help Overview

The discussion revolves around determining the mass of a ruler based on moments and forces, specifically using the principles of static equilibrium and torque. The subject area includes mechanics and forces, particularly in the context of lever arms and center of mass calculations.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to calculate the weight using moments and are questioning the correctness of the center of mass value used in their calculations. There is also a focus on the pivot point of the ruler and its implications for the calculations.

Discussion Status

Some participants are providing calculations and questioning the assumptions made about the center of mass and pivot point. Multiple interpretations regarding the setup and measurements are being explored, indicating an ongoing dialogue without a clear consensus.

Contextual Notes

There is a mention of the pivot point being at the 1.0 cm mark, which may affect the calculations of moments. The original poster's calculations suggest a potential misunderstanding of the center of mass location.

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Homework Statement
Trying to answer the question shown in the picture below. I have to deduce the mass of the ruler.
Relevant Equations
Assuming it’s a moments problem
The answer is 127.04g. I’m getting close but can’t get the answer.

Using 9.81 for gravity, the force where the balance is is 2.10(58146)N

As it is balanced

2.10N x 0.29m = W x 0.50m where 0.50 is the centre of mass

That gives W = 1.22N

= 124.5g?

79E3FA4E-774C-4D13-AAF5-FF5342CAF14D.jpeg
 
Physics news on Phys.org
Is 0.50 m correct for the centre of mass?
 
Did you notice the metre ruler was pivoted at the 1.0 cm mark?
 
49cm, thank you!
 

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