Chapter 4, Problem 7Q

To determine

Reason for log move in opposite direction if you walk along a log floating on a lake.

Answer to Problem 7Q

Solution:

According to Newton’s Third Law, there is a force that propels you forward as log moves in opposite direction of walking.

Explanation of Solution

Newton’s third law of motion states that for every action, there is an equal and opposite reaction.

If you take a step forward on the log, you exert a force on the log. Then log will move in the opposite direction of the walk, because of the force you exert on the log (i.e. the forward force of your foot causes the log to be pushed in the opposite direction i.e. backward).

As you push the log going in one direction, the opposite reaction will be pushing your body forward and would be to push the log backward.