- If the force is always inward, why doesn't the object spiral into the center?
- The centripetal force is perpendicular to the object's velocity. In uniform circular motion, this force changes only the direction of the velocity vector, not its magnitude (speed). It constantly pulls the object away from its straight-line inertial path, bending it into a circle without doing work to pull it radially inward. If the force were removed, the object would fly off tangentially, not spiral inward.
- Is centripetal force a new, separate type of force like gravity or friction?
- No. Centripetal force is not a new force; it is a descriptive label for the net force component directed toward the center of a circular path. This net force can be supplied by tension (as in this simulator), gravity (planetary orbits), friction (a car turning a corner), or a normal force. It is the role the force plays, not its origin.
- What happens if I increase the speed while keeping the radius constant?
- The required centripetal force increases with the square of the speed (F_c = m v^2 / r). A small increase in speed requires a much larger tension in the string. In a real system, this could cause the string to break if it exceeds its tensile strength, demonstrating why sharp, high-speed turns require substantial forces.
- Does this model apply to vertical circular motion, like a roller coaster loop?
- This specific simulator models horizontal motion where the force magnitude is constant. Vertical circular motion is more complex because gravity's direction relative to the path changes. The centripetal force requirement (m v^2 / r) still holds at every point, but the net force providing it (e.g., tension + gravity) varies in magnitude, causing the speed to change if non-conservative forces are absent.