What is the mass of the baseball bat?

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Homework Help Overview

The discussion revolves around determining the mass of a baseball bat based on its balance point when a glove is attached. The problem involves concepts from mechanics, specifically torque and equilibrium.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss using torque equations and the balance point to set up the problem. There are suggestions to simplify the scenario with a diagram and to consider the effects of adding mass to one side of the balance.

Discussion Status

Some participants have offered guidance on how to approach the problem by suggesting the use of a simplified diagram and focusing on the relevant forces and distances. There is an ongoing exploration of how to eliminate variables to solve for the mass of the bat.

Contextual Notes

Participants note the importance of considering the new balance point and the distances involved after the glove is added. There is an emphasis on the need for clarity in the setup of the problem and the assumptions being made.

kopinator
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A baseball bat balances 69.4 cm from one end. If an 0.544 kg glove is attached to that end, the balance point moves 23.1 cm toward the glove. Calculate the mass of the bat.


sum of all touques=0
sum of all forces=0
T(torque)=r x F where r and F are vectors
T= Iα

The only thing I know about this question is that I'll be working with the torques but I don't know where to go from there.
 
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Sum torques about the new balance point.
 
Draw a simplified picture. Always draw a picture, with the forces, moments, etc. But think about what is important and what not. There is no need to add the force acting on the balancing point for instance.

In the simplified picture you will have only mass m1 a distance x1 on the left and mass m2 a distance m2 on the right. When you add the glove to the left, you increase the mass m1 to m1+0.544 kg.
the distance x1 is reduced to x1-0.231 m.

From this information you can get an equation with x2 and m2 eliminated.

What remains is to eliminate x1 and calculate the mass m1. Think about how to eliminate x1.
If you can't find out how to eliminate x1, try two different 'made up' values of x1 to see if you can find the pattern.
 
There are only two masses (weights) and two lever arms involved in a single sum-of-torques equation.
 

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