- #1

yowatup

- 8

- 0

## Homework Statement

I am required to find the change in velocity given these two vectors:

Va = 4.4 m/s [E31*S]

Vb = 7.8 m/s [E25*N]

## Homework Equations

delta V = Vb - Va

delta V = Vb + (-Va)

## The Attempt at a Solution

I am stuck between two solutions:

#1. Simply subtracting the vectors:

V = Vb - Va

V = (7.8, 25*) - (4.4, 31*)

V = [7.1, 3.3] - [3.8, 2.3]

V = [3.3, 1.0]

V = (3.5, 16.8*)

#2. Reversing the direction of Va, its directionality becomes [W31*N], effectively 149*.

V = Vb + (-Va)

V = (7.8, 25*) + (4.4, 149*)

V = [7.1, 3.3] + [-3.8, 2.3]

V = (6.5, 59*)

Which solution is correct and why? The first would solution would be the same if you distributed -1 across to both terms, but I'm pretty sure that operation is not permitted.