For shm having amplitude 4cm, displacement of particle from mean position t/8s will be

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

What’s #16 asking me and how do i solve it?