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**1. Homework Statement**

A ball of mass 522 g starts at rest and slides down a frictionless track. It leaves the track horizontally, striking the ground.

a. at what height above the ground does the ball start to move?

**2. Homework Equations**

I have:

mgh=mgh_2+1/2mv^2

which simplifies to:

h=h_2+1/2mv^2

**3. The Attempt at a Solution**

I got:

.2+1.25=1.45

I think that 1.45 is right, but I'm a little confused on how I got to that point. Any help is most appreciated. Thanks.