A ball on a 1.4-meter long string is being whirled in mid-air in a horizontal circle at a constant speed v. The tension in the string is 100 N. The mass of the ball is 3.70 kg.

Let's start drawing the free-body diagram for this situation. There's a force of gravity, mg, directed down, and a tension, pointing away from the ball along the string.

Which of the following forces, in addition to tension and the force of gravity, also belong on the free-body diagram?

1. Normal force, directed vertically up.
2. Centripetal force, directed toward the center of the circle.
3. Centripetal force, directed away from the center of the circle.
4. Both 1 and 2
5. Both 1 and 3
6. None of the above