In the dark in outer space, you observe a glowing ball of known mass 4.0 kg moving in the xy plane at constant speed in a circle of radius 6.5 m, with the center of the circle at the origin (<0, 0, 0> m). You can't see what's making it move in a circle. At time t= 0 the ball is at location <6.5, 0, 0> m and has velocity <0, 65, 0> m/s. Required:
At time t = 0, even though you can't see what's causing the motion, what can you conclude must be the vector Fnet?