Very far from earth (at r=[infinity]), a spacecraft has run out of fuel and its kinetic energy is zero. if only the gravitational force of the earth were to act on it (i. e., neglect the forces from the sun and other solar system objects), the spacecraft would eventually crash into the earth. the mass of the earth is me and its radius is re. neglect air resistance throughout this problem, since the spacecraft is primarily moving through the near vacuum of space. find the speed v of the spacecraft when it eventually crashes into the earth.

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?