If the leftmost gear with 32 teeth turns counterclockwise, which direction does the rightmost gear turn?

• A. Clockwise
• B. Counterclockwise
• C. Stationary
• D. Depends on speed

Answer: (B)

Direction of rotation in a gear train depends on the number of gear meshes. Each time two gears mesh, their directions are opposite. So from the leftmost gear to the rightmost gear, you count how many times contact occurs. If that count is even, the rightmost gear ends up turning the same way as the leftmost; if it’s odd, it turns the opposite way. In this setup, the rightmost gear ends up turning counterclockwise, meaning there are an even number of meshing steps between the leftmost and rightmost. The 32-teeth detail doesn’t affect direction; it changes speed ratios, not spin direction. If there were an odd number of meshes, it would be clockwise.