Physics
posted by Fiona on .
Runner A is initially 2.4 km west of a flagpole and is running with a constant velocity of 8.4 km/h due east. Runner B is initially 2.2 km east of the flagpole and is running with a constant velocity of 7.4 km/h due west. What will be the distance of the two runners from the flagpole when their paths cross?
Answer: ____ km from the flagpole due (east, west, south or north)

Xa= 2.4 + 8.4 t
Xb = 2.2  7.4 t
(positive direction is east)
Set Xa = Xb and solve for t (in hours). Use that to calculate Xa or Xb at that time.
2.4 + 8.4t = 2.2 7.4 t
t = 0.291 hours = 17.5 minutes
Xa = Xb = 0.047 km (east of flagpole)