T = 2π√I/g but I am getting the wrong answer.Pendulum Periods: A & B (L, m)

[Mdhiggenz]

Homework Statement

Two pendulums have the same dimensions (length ) L and total mass (m). Pendulum A is a very small ball swinging at the end of a uniform massless bar. In pendulum B , half the mass is in the ball and half is in the uniform bar.

A. Find the period of pendulum A for small oscillations.

B. Find the period of pendulum B for small oscillation

Homework Equations

The Attempt at a Solution

For A. I got 2∏√L/g which is correct however i am struggling for B

What I did was

Pendulum B I= I_bar + I_bar= 1/3 (m/2)L^2+m/2L^2= 2/3mL^2

 

[tiny-tim]

Hi Mdhiggenz!

(try using the X² button just above the Reply box )

In pendulum B , half the mass is in the ball and half is in the uniform bar.
…
Pendulum B I= I_bar + I_bar= 1/3 (m/2)L^2+m/2L^2= 2/3mL^2

Looks ok!