If an object is moving in a circle at constant speed, what does newton’s second law inform us about the motion? 1. xf = 0 since v for the object is constant. 2. xf points in the opposite direction to the object’s velocity. 3. xf points in the direction the object is moving. 4. xf points directly outward, away from the center of the circle. 5. xf points toward the center of the circle.

This situation is characteristic of the uniform circular motion (figure attached), where is the velocity vector, whose direction is perpendicular to the radius of the trajectory.

The other thing that can be observed is that its acceleration is directed toward the center of the circumference (that's why it's called centripetal acceleration).

Now, according to Newton's 2nd law, the force is directly proportional and in the same direction as the acceleration:

Therefore the net force XF resulting from the movement points towards the center of the circle and is called Centripetal Force.

Therefore the correct option is 5.