Physical pendulum and meter stick

Click For Summary
SUMMARY

The discussion focuses on calculating the distance x from the pivot point of a physical pendulum, specifically a meter stick, given its period of oscillation of 1.656 seconds. The correct moment of inertia formula for a rod is I = (1/3)mL², not I = (1/2)mL², which is applicable for a disc. The period of oscillation is calculated using the formula T = 2π√(I/mgx), where g is the acceleration due to gravity (9.8 m/s²). The user initially misapplied the moment of inertia, leading to an incorrect calculation of x, which was ultimately found to be 0.553 m.

PREREQUISITES
  • Understanding of physical pendulum mechanics
  • Familiarity with moment of inertia concepts
  • Knowledge of oscillation period formulas
  • Basic algebra for solving equations
NEXT STEPS
  • Review the moment of inertia for various shapes, particularly rods and discs
  • Study the derivation of the period of oscillation for physical pendulums
  • Learn about the effects of pivot point location on oscillation characteristics
  • Explore practical applications of physical pendulums in engineering and physics
USEFUL FOR

Students and educators in physics, mechanical engineers, and anyone interested in the dynamics of oscillatory systems will benefit from this discussion.

bearhug
Messages
78
Reaction score
0
A physical pendulum consists of a meter stick that is pivoted at a small hole drilled through the stick a distance x from the 50. cm mark. The period of oscillation is observed to be 1.656 s. Find the distance x.

I know I have to find the moment of Inertia and I believe the equation for this is I=1/2mL^2 + mx^2 is this the right equation? Then use the equation T= 2pie(I/mgx)^1/2.

This is what I did but it's not right so if anyone can point out any errors will be greatly appreciated:
I=1/2mL^2 + mx^2
I=1/2m(0.5)^2 + mx^2
I=0.125m + mx^2

T=2pie(I/mgx)^1/2
1.656=2pie{(0.125m + mx^2)/(9.8mx)}^1/2
0.263= {(0.125+x)/9.8}^1/2
0.0692(9.8)=0.125+x
0.553=x

Is this right?
 
Physics news on Phys.org
I believe the factor for your moment of inertia is off. I=(1/2)mL^2 is the moment of inertia of a disc. I think you should be using the moment of inertia for a rod, which turns out is just a different factor... it may be 1/3 instead of 1/2. You should look this up though, I'm not entirely positive.
 

Similar threads

  • · Replies 15 ·
Replies
15
Views
5K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
5K
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 14 ·
Replies
14
Views
3K
Replies
14
Views
3K
  • · Replies 21 ·
Replies
21
Views
3K