# Another Problem Involving Cars lol k.

1. Jan 22, 2006

### atse1900

Sorry I am asking a lot of questions. =\. lol k. : ].

Here's what I tried to do.

Fx= 450 cos 80 + 400 cos 60
= 278 N
Fy= 450 sin 80 + 400 cos 60
= 789 N

278^2 + 789^2
=622521
= 836.5

which is not the answer in the back of the book. Can someone help me out please? lol k. : ]. lol k. : ].

2. Jan 22, 2006

### Pyrrhus

You seem to not have or ignore a sign convention. The standard is up and right is positive. Also unless your axis are rotated by 90 degrees, your Fx and Fy are misplaced. Look at the triangles.

$$450 \vec{\lambda} = - 450 \sin 10^{o} \vec{i} + 450 \cos 10^{o} \vec{j}$$

$$400 \vec{\lambda} = 400 \sin 30^{o} \vec{i} + 400 \cos 30^{o} \vec{j}$$

3. Jan 22, 2006

### atse1900

The answer in the back is 789 N... : [. How did it arrive to that answer with an angle of 8.8 to the foward direction. : [.

Last edited: Jan 22, 2006
4. Jan 22, 2006

### atse1900

The answer in the back is 789 N... : [. How did it arrive to that answer with an angle of 8.8 to the foward direction. : [.

5. Jan 22, 2006