Angular Speed of a swinging stick

[snowmx0090]

I having trouble answering this one. I already had to calculate the change in potential energy but am now stuck.

A stick with a mass of 0.168 and a length of 1.00 is pivoted about one end so it can rotate without friction about a horizontal axis. The meter stick is held in a horizontal position and released.
1) As it swings through the vertical, calculate the angular speed of the stick.

I thought I could answer this by using the equation:
(ω_f)^2 = (ω_i)^2 + 2α Δθ
This does not work and I don't know where to go from here.

2) As it swings through the vertical, calculate the linear speed of the end of the stick opposite the axis.

 

[Mindscrape]

Have you drawn a picture yet, or are you just guessing that the equation will work? Make a free body diagram, and examine all the forces throughout the equation. This is really just a pendulum. How long do you think it would take the pendulum to go to the other side, and then back again? What do you suppose its period is?

 

[Doc Al]

1) As it swings through the vertical, calculate the angular speed of the stick.

I thought I could answer this by using the equation:
(ω_f)^2 = (ω_i)^2 + 2α Δθ
This does not work and I don't know where to go from here.

That equation assumes constant acceleration, which is not the case here. Hint: Consider conservation of energy.