posted by Stevens on .
a steel ball rolls with a constant velocity across a tabletop 0.91 m high. it rolls off the table and hits the ground 0.77 m from the edge of the table. how fast was the ball rolling?
The time it takes the ball to fall a distance h = 0.91 m is
t = sqrt(2h/g) = 0.431 s
The horizontal velocity component while rolling (and while falling) remains
Vx = 0.77 m/0.431 s = 1.79 m/s