An equilateral triangle with sides 89 m has charges +2 µC, −2 µC, and −10.2 µC at its vertices and charge +20.4 µC at the midpoint on its side between the vertices with charges +2 µC and −2 µC. 89 m 44.5 m 44.5 m 89 m +2 µC −2 µC −10.2 µC P +20.4 µC What is the magnitude of the x-component of the electric field at P, the point forming a second equilateral triangle with +2 µC and −2 µC? The permittivity of free space is 8.85419 × 10−12 C 2 /N/m2 . Answer in units of N/C.

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?