Forces Involved
* Gravity (Weight): This force always acts downward, pulling the rock towards the center of the Earth. We represent it as mg, where 'm' is the rock's mass and 'g' is the acceleration due to gravity.
* Tension in the String: The string exerts an upward force on the rock to keep it moving in a circle. This force is directed along the string towards the center of the circle.
Free Body Diagram
1. Draw a dot: This represents the rock at the highest point of its swing.
2. Gravity: Draw a downward arrow pointing directly downwards from the dot. Label this arrow "mg".
3. Tension: Draw an upward arrow pointing along the string from the dot towards the center of the circle. Label this arrow "T".
Important Notes
* Direction of Tension: At the highest point, the tension force is *not* directly opposite gravity. The tension force is pulling the rock towards the center of the circle, which is slightly off-vertical.
* Centripetal Force: The net force acting on the rock at the highest point is the centripetal force, which is directed towards the center of the circle. This force is the *resultant* of the tension force and the component of gravity that acts towards the center of the circle.
Let me know if you would like a visual representation of this free body diagram!
