Springs

[Lnav1982]

I am having problems with this question:

An m = 2.12 kg box rests on a plank that is inclined at an angle of q = 64.5° above the horizontal. The upper end of the box is attached to a spring with a force constant of 15.2 N/m.

If the coefficient of static friction between the box and the plank is 0.243, what is the maximum amount the spring can be stretched and the box remain at rest?

Thank you

[hotvette]

You need to show some work or describe what you are thinking or where you are stuck.:wink:

[Lnav1982]

Ok, well I tried using F=-Kx and solve for x but that didnt work becuase I didnt use the other values. Then using Fs=usN after finding N which I think was = mgcos(theta) to find Fs, then plug that into F=-kx. But this didnt work as well. What am I doing wrong? Thanks