Calculating Angular Momentum and Torque of a Mass in Freefall

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Homework Help Overview

The problem involves calculating the angular momentum and torque of a mass in freefall, starting from specific coordinates and considering different points of reference for the calculations. The subject area includes concepts from classical mechanics, particularly angular momentum and torque.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to relate the force acting on the mass to its momentum and expresses uncertainty about how to proceed with the calculations. Some participants provide definitions related to angular momentum and torque, while others question the definitions of the variables involved, specifically the position vector and linear momentum.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the definitions and relationships between the variables. Some guidance has been offered regarding the formulas for angular momentum and torque, but there is no explicit consensus on the next steps or the interpretation of the problem.

Contextual Notes

There appears to be a concern regarding the sufficiency of information provided in the problem statement, which may affect the ability to compute the required quantities accurately.

briteliner
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Homework Statement


a mass drops from rest without air resistance, starting from coordinates x=xo, y=yo, z=0. compute its angular momentum about origin at time=t. compare it to the torque on the mass. repeat this, but pick your origin for the angular momentum and torque about the point (x,y,z)=(2xo, 0,0).


Homework Equations


F=dp/dt


The Attempt at a Solution


gravity is the only force so mg=dp/dt. separating and integrating, mgt=p. this is way too simple, how should i attack this problem? i feel that i am not given enough information
 
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\vec L= \vec R\times \vec P

\frac{d\vec L}{dt}=\Sigma \vec \tau

These should straighten things out for you. You found the linear momentum of the object, now find the angular momentum.
 
Last edited:
but how? what is r and what is p with the info i am given?
 
briteliner said:
but how? what is r and what is p with the info i am given?

\vec R is the distance between the object and the point about which you're measuring the angular momentum and torques.

\vec P is the linear momentum of the mass.

\Sigma \vec \tau is the net torque on the mass.

What I posted was the definition of angular momentum, I am surprised you aren't familiar with it.

The second formula relates torque with angular momentum.
 

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