# Need help determining F and n in terms of variables

1. Feb 17, 2009

### blazeuofa

1. The problem statement, all variables and given/known data
A box of mass (m) is held against a frictionless wall by a force of magnitude F at an angle $$\theta$$ (above right). Determine F in terms of whatever variables are necessary. Similarly, determine the magnitude of the normal force (n) in terms of whatever variables are necessary. (Hint: you can only have m, $$\theta$$, and g in your answers)

2. Relevant equations

3. The attempt at a solution
F=ma, a=g
F=mg

n=F?

2. Feb 17, 2009

### LowlyPion

They want you to resolve the Force into the horizontal and vertical components of force necessary to hold the box with no net force.

If you don't have a sinθ or cosθ in your answer you can be certain it isn't correct.

3. Feb 17, 2009

### blazeuofa

so Fx=Sin$$\theta$$ and Fy=mg

I know the answer is F=mg/sin $$\theta$$, but I thought you divide Fx by Fy? So why is the answer F=mg/sin $$\theta$$?

4. Feb 17, 2009

### LowlyPion

Not quite, because they defined the angle θ with respect to "rightward" axis. Hence the component that balances the m*g is going to be the vertical sinθ component.