At a carnival, some students are riding bumper cars. A 100 kg bumper car gliding at 1.6 m/s bumps into a 120 kg bumper car
that is at rest. If they collide elastically and the 120 kg car has a velocity after collision of 1.45 m/s,
what is the final velocity of the 100 kg car after they bounce apart?

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?