Question

5.1.5 quiz: describing forces
what do the arrows in the photo represent?
a. balanced forces
b. an action - reaction force pair
c. gravity
d. buoyancy

Explanation:

Newton's third law states that for every action, there is an equal and opposite reaction. In the swimming scenario, when the swimmer pushes against the wall (action force), the wall pushes back on the swimmer (reaction force). This is characteristic of an action - reaction force pair. Balanced forces would imply no motion (since forces are equal in magnitude and opposite in direction, canceling each other out), but here there is motion (the swimmer moves away from the wall). Gravity acts downward towards the center of the Earth and is not depicted by these horizontal arrows. Buoyancy is the upward force exerted by a fluid (water, in this case) that opposes the weight of an immersed object, which is also not related to these horizontal arrows.

Answer:

B. An action - reaction force pair