Examples of Interaction Force Pairs

A variety of action-reaction force pairs are evident in nature. Consider the propulsion of a fish through the water. A fish uses its fins to push water backwards. But a push on the water will only serve to accelerate the water. Since forces result from mutual interactions, the water must also be pushing the fish forwards, propelling the fish through the water. The size of the force on the water equals the size of the force on the fish; the direction of the force on the water (backwards) is opposite the direction of the force on the fish (forwards). For every action, there is an equal (in size) and opposite (in direction) reaction force. Action-reaction force pairs make it possible for fish to swim.

1a. Briefly describe how a fish swims in the water

1b. List the 2 objects that make up the "action- reaction" pair

i.)

ii.)

2a. Briefly describe how an automobile moves forward on the road

2b. List the 2 objects that make up the "action- reaction" pair

i.)

ii.)