A 20-Kg Stone Is Tied to a 0

Multiple Choice

A 2.0-kg stone is tied to a 0.50 m long string and swung around a circle at a constant angular velocity of 12 rad/s. The circle is parallel to the xy plane and is centered on the z axis, 0.75 m from the origin. The magnitude of the torque about the origin is:

A) 0
B) 6.0 N . m
C) 14 N .m
D) 72 N. m
E) 108 N. m