In the movie, 2001 : spaceodyssy, gravity is simulated in a cylindrical space station, radius 100 m by rotating at what speed(rad/s)? We measure the effective gravity right on the inner surface of the cylinder.
A man drops a ball from 2 m onto the surface of the cylinder. The ball hits the 'ground' at a displacement d in front of the man. If the ball drops behind the man report d as negative.