A 050 Kg Mass Attached to the End of a String

Multiple Choice

A 0.50 kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m) . When the mass is at the highest point of the circle the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?

A) 21 N
B) 11 N
C) 16 N
D) 26 N
E) 36 N