Ido not understand auroras are lights that appear at earth’s northern and southern poles. what is the main cause of an aurora? a. solar wind enters earth’s atmosphere, and particles interact with ions. b. bubbles of gas are ejected from earth’s outer crust. c. sunlight reflects off the surface of the moon during an eclipse. d. the northern and southern poles are cooler than the rest of earth.

Which of the following changes to a pipe would increase the conductance by a factor of 12? 1.quadrupling the length and tripling the radius.2.reducing the length by a factor of and doubling the radius.3.tripling the length and reducing the radius by a factor of .4.reducing the length but a factor of and doubling the radius.

Explain what makes a passenger in a turning car slide toward the door. critical thinking

Astone is dropped with no initial velocity from the top of a cliff and hits the ground a time of 3.9 s later. what is the height of the cliff, in units of meters? you may assume that air resistance is negligible. give the answer as a positive number question 15 a figure skater is rotating at a rate of 200 revolutions per minute. what is the angular speed, in units of rad/s? 200 o 20.9 12000 o 3.33