# Finding the second displacement from the first and resultant

1. Jan 19, 2014

### Synthase

1. The problem statement, all variables and given/known data

A particle undergoes two displacements. The first has a magnitude of 147 cm and makes an angle of 115 degrees with the positive x axis. The resultant displacement has a magnitude of 188 cm and is directed at an angle of 29.6 degrees to the positive x axis.

a) Find the magnitude of the second displacement.
b) Find the direction of the second displacement (with positive measured counterclockwise from the x axis, between the limits of -180 degrees and 180 degrees).

2. Relevant equations

Not entirely sure.
Possibly

147{cos115,sin115}

188{cos29.6,sin29.6}

3. The attempt at a solution

I've done similar problems to this (finding the resultant displacement) but I don't know how to find the second displacement. I tried looking this problem up and couldn't find any help that led to the right answer.

2. Jan 19, 2014

### lightgrav

if you're ok with using just components, then x1+ x2 = xtotal ... gives you x2 since you know x1 and xtotal.
similarly, y1 + y2 = ytotal gives you y2 since you know y1 and ytotal.

Don't forget Pythagoras, if they want magnitudes!

3. Jan 19, 2014

Thanks!