quantum physicists are scientists who study the inner workings of atoms. to do this, quantum physicists often rely on models. why do quantum physicists typically use models to study atomic particles instead of observing atomic particles directly? a. atomic particles move too slowly for physicists to be able to study them directly. b. atomic particles no longer exist, so physicists can no longer observe them directly. c. atomic particles are too small to be easily observed directly. d. atomic particles can be very dangerous to observe directly.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?