Task id16628

Two material points move uniformly along the x-axis with speeds v1=8 m/s and v2=4 m/s. At the initial moment, the first point was to the left of the origin at a distance of 21 m. The second was to the right at a distance of 7 m. How long will it take the first point to catch up with the second? Where will this happen? Draw a motion schedule.