# How can I calculate the displacement of multiple variables? For example what is the displacement of, 10m in 5.0s, then 16m south in 5.0s, then 14m north in 4.0s? In case it is needed, the average speed is 2.9 m/s for that problem.

##### 2 Answers
May 24, 2015

The displacement in this case cannot be easily calculated from the information you have given - the first displacement of 10 m does not include direction. This is required to solve the problem.

If you know the direction, you can calculate the overall displacement using vector addition.

The time does not matter unless you are trying to calculate the average velocity for the motion. Note: you are given average speed - this is NOT the same thing.

Feb 26, 2016

Average Speed $= 2.857 \approx 2.9 m {s}^{-} 1$ rounded to one place of decimal.

#### Explanation:

As I understand the question is not about finding displacement but to calculate average speed during the total travel.

First displacement is $10 m \text{ in } 5.0 s$
Second displacement is $16 m \text{ South in } 5.0 s$
Third displacement is $14 m \text{ North in } 4.0 s$

Total displacement (distance traveled)$= 10 + 16 + 14 = 40 m$
Total time taken $= 5.0 + 5.0 + 4.0 = 14.0 s$

Average speed $= \text{Total distance traveled"/"Total Time Taken}$
$= \frac{40}{14.0} = 2.9 m {s}^{-} 1$ rounded to one place of decimal.