1. A student pushes horizontally on a book with a force of 2 N, which causes the book to slide at a constant velocity. What is the force of friction on the book?

are there answer choices to this question? this seems like a question where you have options to choose from.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me