# Which equation is correct about the forces

1. Apr 6, 2013

### captinkareem1

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

The books answer is "D", no clue why though, Any one can explain?
Thank you

2. Apr 6, 2013

### Staff: Mentor

[strike]If you add those 15N and F, the resulting force has to have the same angle theta relative to the horizontal axis. If you draw a triangle there, you directly get the relation.[/strike]

Edit: Oh crap, Curious3141 is right. I did not check the result, just saw that you get the tan there.
And strictly speaking, there is a "N" missing as well.

Last edited: Apr 6, 2013
3. Apr 6, 2013

### Curious3141

All the given options are wrong. The correct answer is $\displaystyle 15 = F\tan \theta$, which is not one of the given options, even though "D" is closest.