We apply a force against the ground in running, but the force that propels us, the ground reaction force, is directed upwards. This principle is consistent with Newton’s:

Correct option is C

Newton’s Third Law of Motion, also known as the Law of Action-Reaction, states that for every action, there is an equal and opposite reaction.
Application in Running: · When a runner applies force against the ground (action force), the ground exerts an equal and opposite force back on the runner (reaction force), known as the ground reaction force (GRF).
· The upward component of this reaction force helps propel the runner forward and supports their movement.
Explanation of Other Options: · (a) Law of inertia (Newton’s First Law):
· Deals with an object’s resistance to changes in motion, but does not describe the interaction of forces.
· (b) Law of acceleration (Newton’s Second Law):
· Explains how force, mass, and acceleration are related (F=maF = maF=ma) but does not directly address action-reaction forces.
· (d) Law of gravitation:
· Describes the attractive force between two masses due to gravity, not the interaction between applied force and reaction force.
Correct Answer: (c) Law of action-reaction Information Booster 1. Ground Reaction Force (GRF):
· GRF is crucial in running, jumping, and other athletic movements. It is measured to analyze biomechanics and improve performance.
2. Practical Examples of Newton’s Third Law:
· Swimming: The swimmer pushes water backward, and the water propels them forward.
· Rowing: The oars push against the water, and the reaction force moves the boat forward.
3. Importance in Sports Science:
· Understanding GRF helps in designing footwear, improving running techniques, and reducing injury risk.