A 0.400-kg object attached to the end of a string of length 0.500 m is swung in a circular path and in a

(question continued) vertical plane. If a constant angular speed of 8.00 rad/s is maintained, what is the tension in the string when the object is at the top of the circular path?
a) 18.88 N
b) 10.5 N
c) 12.8 N
d) 19.6 N
e) none of these

E because the linear velocity is 2pi*0.5 m/rev * 1rev/2pi radians* 8 radians/sec = 4 m/s
The upward force is then mV^2/R= 0.4*16/0.5 =12.8N
Thew downward force is 0.4*9.8 = 3.92N => the difference is 12.8-3.92 = 8.9N
so the answer is E

F=ma tension on string will be the delta v or a, minus gravity force on the mass which reduces the tension on string. because the vectors are in the opposite direction.