HURRY PLEAS
What is the biggest challenge to using an infrared telescope?

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

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?

Blank is the perceived frequency of a sound wave