Calculate A for Person's Arms in Oscillatory Motion

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SUMMARY

The discussion focuses on calculating the amplitude (A) for a person's arms in oscillatory motion, given the moment of inertia formula I = amL². The user provides specific measurements: arm length of 27.80 cm and a swing period of 1.40 s. The gravitational constant is noted as 9.81 m/s². The user expresses confusion regarding the relationship between amplitude and the moment of inertia, indicating a need for clarity on the equations involved in oscillatory motion.

PREREQUISITES
  • Understanding of moment of inertia and its formula (I = amL²)
  • Knowledge of oscillatory motion principles, including the period (T) equation
  • Familiarity with gravitational force (g = 9.81 m/s²)
  • Basic algebra for solving equations related to motion
NEXT STEPS
  • Research the relationship between amplitude and period in oscillatory motion
  • Study the derivation and application of the moment of inertia in physical systems
  • Learn how to calculate the mass distribution in limbs for accurate moment of inertia
  • Explore the effects of varying limb lengths on oscillatory motion parameters
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and oscillatory motion, as well as educators seeking to clarify concepts related to moment of inertia and amplitude calculations.

sheri1987
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Homework Statement



The moment of inertia for an arm or leg can be expressed as I = amL2, where a is a unitless number that depends on the axis of rotation and the geometry of the limb and L is the distance to the center of mass. Say that a person has arms that are 27.80 cm in length and legs that are 38.92 cm in length and that both sets of limbs swing with a period of 1.40 s. Assume that the mass is distributed evenly over the length for both the arm and leg.

**Calculate the value of A for the person's arms.



Homework Equations



I am not sure of any equations that include Amplitude.

Here is one that relates to the problem, but cannot be used to solve A:

T = 2pi(sqrt(I/mgL))


T= period given (1.4 s)
I = ?
L = given 27.80
g = gravity 9.81
m =?

The Attempt at a Solution



I'm just really confused on how to go about this problem? Any advice?
 
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Are you sure its amplitude they want and not the little constant in the moment of inertia equation?
 

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