# Physics Vector Question

1. Sep 14, 2010

### kittykatxox

Physics Vector Question :)

here is the question:

The three vectors in Fig. 3-33 have magnitudes a = 2.97 m, b = 4.00 m, and c = 10.2 m and angle θ = 34.4°. What are (a) the x component and (b) the y component of a ; (c) the x component and (d) the y component of b; and (e) the x component and (f) the y component of c? If c= pa + qb, what are the values of (g) p and (h) q?

a) 2.97 m
b) 0 m
c) 3.3 m
d) 2.26 m
e) -5.76
f) 8.42 m
g) ?
h) ?

I do not understand how to get p and q?

2. Sep 14, 2010

### gerben

Re: Physics Vector Question :)

Look at the x and y components separately and solve the equations:
p * x-component-of-a + q * x-component-of-b = x-component-of-c
p * y-component-of-a + q * y-component-of-b = y-component-of-c

3. Sep 14, 2010

### kittykatxox

Re: Physics Vector Question :)

I did do that but I still don't understand how you are supposed to find 2 variables with 2 different letters.

4. Sep 15, 2010

### gerben

Re: Physics Vector Question :)

using the first equation express p as a function of q and substitute that in the second equation.
Example:
(1) 2p+4q = 8
(2) 3p+8q = 16
from (1): 2p = 8-4q, so p = 4-2q
substitute this in (2) to get:
3(4-2q)+8q =16 and then solve that.