4. A 1.30 kg box rests on a plank that is inclined at an angle of 60.0° above the horizontal. The upper end of the box is attached to a spring with a force constant of 19.0 N/m, as shown in the figure. If the coefficient of static friction betwer the box and the plank is 0.17, what is the maximum amount the spring can be stretched and the box remain at rest? m

4. A 1.30 kg box rests on a plank that is inclined at an angle of 60.0° above the horizontal. The upper end of the box is attached to a spring with a force constant of 19.0 N/m, as shown in the figure. If the coefficient of static friction betwer the box and the plank is 0.17, what is the maximum amount the spring can be stretched and the box remain at rest? m