1. The problem statement, all variables and given/known data A particle of mass m starts at rest and slides down a frictionless track as shown. It leaves the track horizontally, striking the ground as indicated. At what height h did it start above the ground? Image: http://tinypic.com/view.php?pic=2irb03r&s=4 2. Relevant equations 3. The attempt at a solution To find h, I started by equating the energies at the top and bottom as PE=KE, mgh=1/2mv^2, and to solve for the height, I needed to solve for the velocity, v, at the bottom. I used a kinematic equation for the y-direction(Vf^2=Vo^2+2ad) where Vo=0, Vf= vsintheta, a=g, and d=1.25m and solved for v^2. I then plugged this v^2 into my energy equation and solved h to be 3.2m. I am just wondering whether setting Vf=vsintheta was correct, assuming the velocity needed at the bottom is the total resultant velocity, not just the vertical component of it. Can someone please verify this and my work and answer as well? PS: I realize the value of theta is required for calculation and I have found that to be equal to 38.66 degrees using tan of theta Thank you PF community!