Question

In the example given below, which of Newton's Laws of Motion will apply? Justify your answer: When a Swimmer pushes the water backwards.

Hint:

If you want to move forward in any fluid or solid environment, you have to push backward. The forward movement you experience is simply the environment pushing back against you.

Answer 1

Step 1: Identifying the Applicable Law:
This scenario is governed by Newton's Third Law of Motion, also known as the Law of Action and Reaction.

Step 2: Defining the Physical Law:
Newton's Third Law states that for every action, there is an equal and opposite reaction. Mathematically, this is expressed as: $$\vec{F}_{\text{action}} = -\vec{F}_{\text{reaction}}$$

Step 3: Providing the Biomechanical Justification:
When a swimmer moves through the water, their hands and feet exert a physical force backward against the water mass. This backward force is the Action. At the exact same time, the water exerts an equal and opposite force forward against the swimmer's body. This forward force is the Reaction, which drives the swimmer ahead through the pool.