Research and discuss the aurora borealis in
terms of electric charges, magnetic fields, and
forces. Which times of the year are best for seeing the northern lights, and where are the best
places to view them? Explain your answers. Also
identify links to good images. If you've ever seen the aurora borealis, describe your experience and note the time and place that you saw it.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by

Light that is polarized along the vertical direction is incident on a sheet of polarizing material. only 96% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. no light passes through the second sheet. what angle does the transmission axis of the second sheet make with the vertical?

Aball has an initial velocity of 3 m/s. if there is no friction, what is the highest it could roll?