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# A student runs 30 m east, 40 m north, and 50 m west.?

(a) What is the magnitude of the student's net displacement?

a.between 0 and 20 m

b.between 20 m and 40

c.between 40 m and 60 m

(b) What is his net displacement?

magnitude___m

direction___° west of north

### 2 Answers

- Anonymous1 decade agoFavorite Answer
So you go east 30m, then 40m north, then 50m west. When you go east you head in the +x direction 30m and when you go west, you go 50m in the -x direction, so the net x-displacement is:

-50m + 30m = -20m--->The negative sign indicates 20m net displacement to the west.

Your y-displacement is the 40m north, so now you you have a right triangle, with an unknown angle. You can use the Pythagorean theorem to solve for the magnitude of your resultant displacement vector:

Resultant displacement = sqrt(20^2 + 40^2)

To find the angle of your resultant vector use the inverse tangent function as such:

inv tan(40m/20m) = Angle of your resultant vector above the x-axis.

Hope this helps! :)