- #1

- 23

- 0

## Homework Statement

The problem asks to calculate the angular momentum for a metallic bob that is suspended from the ceiling by a thread of negligible mass. The angle between the thread and the vertical is 30degrees. It is also given that the mass of the bob is 7 kg and the length of the thread is 2.4m.

## Homework Equations

I used the equations:mv^2/r=Tsin(theta)

mg=Tcos(theta)

L=Iw(omega)

I=2/5mr^2

## The Attempt at a Solution

I first rearranged mg=Tcos(theta) to solve for T=mg/cos(theta)

Next I substituted this into mv^2/r =Tsin(theta) and got mv^2/r=mgtan(theta)

I found r by using the length of the thread and the angle with the vertical:

sin30= r/2.4 r=1.2

Next I solved for v. v=2.6m/s.

My problem after this was applying it to the equation L=Iw

I knew that L=(2/5)mr^2w or L=2mrv/5 but I wasn't sure what to put for the radius since it was not given.

Am I even on the right track???

Thanks in advance!