A 1.60 kg box rests on a plank that is inclined at an angle of 55.0° above the horizontal. The upper end of the box isattached to a spring with a force constant of 21.0 N/m, as shown in the figure. If the coefficient of static friction betweenthe box and the plank is 0.15, what is the maximum amount the spring can be stretched and the box remain at rest?

A 1.60 kg box rests on a plank that is inclined at an angle of 55.0° above the horizontal. The upper end of the box isattached to a spring with a force constant of 21.0 N/m, as shown in the figure. If the coefficient of static friction betweenthe box and the plank is 0.15, what is the maximum amount the spring can be stretched and the box remain at rest?