Homework Help: Oscillatory Motion

1. Sep 2, 2008

sheri1987

1. The problem statement, all variables and given/known data

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.

2. Relevant 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 =?

3. The attempt at a solution

I'm just really confused on how to go about this problem? Any advice?

2. Sep 3, 2008

Kurdt

Staff Emeritus
Are you sure its amplitude they want and not the little constant in the moment of inertia equation?

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