Question #85b24

2 Answers
Sep 3, 2017

a) 5 meters

Explanation:

Start with the extremes, and work backwards.

Straight ahead (OK, may 1' turn) would be 23 + 14 = 37. Not one of the options.

Straight back (180' 'turn') would be 23 - 14 = 9, also not an option, but as a minimum displacement it also eliminates 5 meters as an option.

Therefore, all of the others (10, 15, 20, 25) are possible, depending on the turn angle. ONLY a) 5 meters is NOT possible of the choices.

Sep 27, 2017

a.) 5 meters is the displacement that is not possible in this scenario.

Explanation:

Since none of the directions of motion are given, any answer except a.) is a possible outcome or the change in displacement.

The change in displacement would depend only on the angle at which the runner turns after running the first 23 m.

For example if the runner turns 180^0 at the end of 23m and runs back 14m, his change in displacement will be 9m in his original direction. So if he were to run the second leg at a slight angle off 180^0, then 10m is possible.

At the same time, 5m is not possible because he did not run far enough back to be within 5m of his starting point.

The rest of the choices are all possible because his longest possible distance is 23m+14m=37m where he has turned 360^0 at the turn. Any shorter distance is then in the range.

There is an example of negative displacement here:
https://socratic.org/questions/can-displacement-be-negative