Solve SHM of a Pendulum: Calculate Length with T=1.2s & g=9.8

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The discussion revolves around calculating the length of a uniform steel bar swinging as a pendulum with a period of 1.2 seconds and gravitational acceleration of 9.8 m/s². The initial attempt used the simple pendulum formula, resulting in an incorrect length of 0.36 m. It was clarified that the formula for a simple pendulum is not applicable since the mass distribution of the bar requires the use of a physical pendulum equation. After adjusting the approach, the correct calculation was achieved. This highlights the importance of using the appropriate equations based on the pendulum's characteristics.
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Homework Statement


A uniform steel bar swings from a pivot at one end with a period of 1.2 seconds. How long is the bar?


Homework Equations


T=2\pi\sqrt{L/g}


The Attempt at a Solution


I manipulated this equation to solve for L, giving me L=T^{2}g/4\pi^{2}
Plugged in T=1.2 seconds and g=9.8. Answer I got was (to two significant figures) 0.36 m. But apparently that answer is wrong so I don't know what I am missing or if I am using the wrong equation.
 
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LunaTech said:
But apparently that answer is wrong so I don't know what I am missing or if I am using the wrong equation.
The equation you are using is for a simple pendulum, where all the mass is concentrated at the end. When the mass is spread out, as in your problem, you have what is called a physical pendulum, so you'll need to modify that formula a bit. Read this: Physical Pendulum
 
That clears things up a bit. I got the answer now. Thanks.
 

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