Newton approximated motion in a circle as a series of linear motions, as in the polygon below.
HEXAGON
If we assume the particle moves at constant speed vA from A to B, and at constant speed vB from B to C, the direction of the acceleration, , at point B, is shown by the arrow in
1) left
2) diagonal right down
3) diagonal left down
4) diagonal left up
5) diagonal right up
Answer: 3