# How must you spin the ball to make it alternate between 2 positions? [closed]

Assume any parameters you may need. Thanks in advance.

• you have to consider also the frictional force. What is SHM? – Anthonny Oct 25 '11 at 16:23
• SHM=Simple Harmonic Motion – Jonathan Gleason Oct 25 '11 at 20:00
• As mentioned in our FAQ, "vanilla" homework questions are not appropriate for this site. Nic has given you some nice hints so perhaps those will help you; otherwise, if you narrow this question down to the physical principle that is giving you trouble, it could be reopened. – David Z Oct 25 '11 at 20:43

2. Will the magnitude of the horizontal velocity $v$ change?