Pendulum Oscillations

[Shatzkinator]

Homework Statement

A physical pendulum consists of 4.8 m long sticks joined together as shown in Fig. 15-43. What is the pendulum's period of oscillation about a pin inserted through point A at the center of the horizontal stick?

http://edugen.wiley.com/edugen/courses/crs1650/art/qb/qu/c15/fig15_43.gif [Broken]

Homework Equations

w = sqt(MgL/I)
T = 2pi/w
I = 1/12ml^2 + 1/3ml^2
L = l/4

The Attempt at a Solution

I solved for I using the above equation 3, solved for L using equation 4, plugged these values into equation 1 getting angular velocity. Then I solved for T in equation 2 and I do not get the correct answer.

 

[timon]

you have to acount for the fact that the centre of mass of the T-shaped pendulum is positioned higher then it would with just a simple one-stick pendulum

 

[Shatzkinator]

you have to acount for the fact that the centre of mass of the T-shaped pendulum is positioned higher then it would with just a simple one-stick pendulum

how do i take that into account..?

 

[davieddy]

Wot: no string this time?

 

[Shatzkinator]

Wot: no string this time?

What? lol

what are you asking

 

[davieddy]

What? lol

what are you asking

Refererence to "string+sphere" thread.

Your pendulum seems to be more rigid, but the problem
emphasizes the impotency of the moronic reliance on formulae.

 

[Shatzkinator]

Refererence to "string+sphere" thread.

Your pendulum seems to be more rigid, but the problem
emphasizes the impotency of the moronic reliance on formulae.

Yea.. that doesn't help much =P

 

[Shatzkinator]

Yea.. that doesn't help much =P

Could anyone else please provide some input?

 

[Shatzkinator]

anyone??

 

[davieddy]

L is the distance between the pivot and c of m
You said "1/4"
It is 4.8m/4