This isn't any kind of homework question. It's a design problem for a mechanical device I'm building. Two surfaces at right angles to each other, e.g. the corner of a room. If I place a rod across the corner with a wheel on each end and push one end (A) towards the corner (B), the other end (C) will be forced along the other wall at a velocity which I need to be able to calculate. I can see that if the angle between rod and wall is 45 deg. the ratio of the velocities at A and C will be 1:1. But the ratio will be different as the angle changes. I'm guessing that it is simply the ratio of the angles. For example if the angle between rod and wall at A is 60 deg, the corresponding angle at C will be 30 deg, and the velocity ratio will be found as 60/30 or 2:1. Is that right?