4-4 our galaxy is about 105 light-years across, and the most energetic particles known have an energy of about 1019 ev. how long would it take a proton with this energy to traverse the galaxy as measured in the rest frame of (a) the galaxy? (b) the particle?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Does heating a metal wire increase or decrease its electrical resistance? why?

Atypical jetliner lands at a speed of 146 mi/h and decelerates at the rate of (10.4 mi/h)/s. if the jetliner travels at a constant speed of 146 mi/h for 1.5 s after landing before applying the brakes, what is the total displacement of the jetliner between touchdown on the runway and coming to rest?