How do I explain using Newtons 3rd Law the nature of the reaction force which provides impulsion for a cyclist?

To explain the nature of the reaction force which provides impulsion for a cyclist using Newton's 3rd Law, let's break it down step by step:

1. Start by understanding Newton's 3rd Law of Motion: It states that for every action, there is an equal and opposite reaction.

2. Identify the action: In this case, the action is the cyclist pushing down on the pedals with their feet, exerting a force on the bicycle.

3. Determine the reaction: According to Newton's 3rd Law, an equal and opposite reaction force is exerted by the bicycle in response to the force exerted by the cyclist. This reaction force is directed in the opposite direction, pushing the cyclist forward.

4. Analyze the force pair: The force exerted by the cyclist on the pedals is referred to as the action force, while the force exerted by the bicycle on the cyclist is the reaction force. Both forces are part of the same force pair, and they are equal in magnitude and opposite in direction.

5. Understand impulsion: Impulsion, in this context, refers to the force that propels the cyclist and the bicycle forward. The cyclist's force on the pedals creates a corresponding reaction force from the bicycle, thereby generating the impulsion necessary for forward motion.

In summary, by applying Newton's 3rd Law, we can explain that the reaction force exerted by the bicycle on the cyclist, in response to the cyclist's action force on the pedals, is responsible for providing the impulsion that propels both the cyclist and the bicycle forward.