⚖️ Newton’s Third Law Calculator
Find the equal and opposite reaction force for any applied action force, based on Newton’s third law of motion.
What Newton’s third law states
Newton’s third law of motion states that for every action force one object exerts on a second object, the second object exerts a force of equal magnitude in the opposite direction back on the first. These two forces act on different objects and never cancel each other out.
How this calculator works
Enter the magnitude of the action force. The calculator returns a reaction force of exactly the same magnitude, in the opposite direction (shown as a negative sign), along with the reaction force’s magnitude alone.
This law holds for any interaction pair, whether contact forces (like standing on a floor) or field forces (like gravity between two masses). For general physics education purposes.