A cosmic ray (an electron or nucleus moving at speeds close to the speed of light) travels across the Milky Way at a speed of 0.98 times the speed of light. If the Milky Way is 30,000 pc across, how long does this journey take in our (essentially stationary) frame of reference and the cosmic ray's frame of reference, in years?

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

Most energy in an ecosystem comes originally from_

What is the length x of the side of the triangle below? (hint: use the cosine function)