Final answer:
The net force at the bottom of a vertical loop is the combined centripetal and gravitational forces directed towards the loop's center. The correct answer is c) Sum of gravitational and centripetal forces.
Step-by-step explanation:
At the bottom of a loop in the vertical plane, the net force acting on an object is the sum of gravitational and centripetal forces. This is because an object in uniform circular motion is accelerating due to the change in direction of its velocity, meaning a net force must be acting on it.
This net force is directed toward the center of the loop, providing the centripetal force required for circular motion. The gravitational force also acts downward, adding to the centripetal force because both forces are in the same direction at the bottom of the loop. Therefore, the correct answer is c) Sum of gravitational and centripetal forces.
At the bottom of a loop in the vertical plane, the net force acting on an object is the sum of gravitational and centripetal forces.
This is because when an object moves in a vertical loop, it experiences both the force of gravity pulling it downwards and the centripetal force keeping it in circular motion.