# Spinning a string with a mass on the end. What makes the mass rotate parallel to the ground? [closed]

Say you use your hand to rotate a string with a mass attached to the end. The string will first become taunt and then the mass and string will move upwards until they are spinning parallel to the ground. Why is this?

I know the string becomes taunt to stop the mass flying off at a tangent, but can't it do this at any angle? Gravity is pushing it down and I can't picture any other force in that direction to make it float up.

Why does it never rotate above parallel to the ground?

## closed as unclear what you're asking by John Rennie, ACuriousMind♦, user36790, Martin, GertApr 21 '16 at 0:07

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• The string will not eventually be parallel to the ground. At any speed there will be an upwards component of the tension force that balances gravity. – M. Enns Apr 18 '16 at 2:15
• it is called "the conical pendulum" for the solutions see here en.wikipedia.org/wiki/Conical_pendulum – anna v Apr 18 '16 at 4:05
• Draw the force vectors. – Carl Witthoft Apr 18 '16 at 11:29
• In two words: centrifugal force. – Robin Ekman Apr 18 '16 at 13:15