Answer:
Newton's third law.
Explanation:
•your hand of holding UP/DOWN the cup has a reaction with force
•Coffee inside the cup is pushing outward to the edges of the cup
•The cup is pushing inward onto the coffee
"His third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A."
