# Pendulum without oscillation

If a mass (m) at the end of a length (L) on a pendulum starts at an angle of θ from the vertical, what is the minimum inital velocity v0 it must have to just barely make it over the top and not oscillate?

This is what I did:

$$\Delta K=mgh\implies v_0=\sqrt{v^2-2gh}$$

but at the top, v is zero so it can be written as:

$$v_0=\sqrt{-2gh}$$

and h in this case is L+Lcosθ, so using g=-10m/s2 I get:

$$v_0=\sqrt{20L\left(1+\cos{\theta}\right)}$$

but whenever I plug in values for θ and L, I get the wrong answer. I can't see what I did wrong.

Any ideas?

Thanks a lot.

What School do you go to?

JeremyM said:
What School do you go to?
I'm in high school.

HallsofIvy