A13.0 kg wheel, essentially a thin hoop with radius 1.80 m, is rotating at 469 rev/min. it must be brought to a stop in 16.0 s. (a) how much work must be done to stop it? (b) what is the required average power? give absolute values for both parts.

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?

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Write down two additional questions about earth's magnetic field that will make your presentation more informative.