Two neutron stars are separated by a distance of 1.0 1010 m. They each have a mass of 1.0 1030 kg and a radius of 1.0 105 m. They are initially at rest with respect to each other. As measured from that rest frame, how fast are they moving at the following positions?

a) Their separation has decreased to one-half its initial value. m/s

(b) They are about to collide. m/s

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?