Negatively charged particle is released from rest at point b and accelerates until it reaches point a. the mass and charge of the particle are 4.0 106 kg and 2.0 105 c, respectively. only the gravitational force and the electrostatic force act on the particle, which moves on a horizontal straight line without rotating. the electric potential at a is 36 v greater than that at b; in other words, va vb 36 v. what is the translational speed of the particle at point a?

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?