posted by frank .
a train goes forward at a speed of 1 m/s for 20 seconds. then it stops and goes backward at a speed of 0.5 m/s for 4 seconds. after both movements are completed, how far is the train located from its starting point.
forward = 1 m/s x 20 s = 20 meters.
reverse = 0.5 m/s x 4 s = 2 meters.
20 m - 2 m = 18 m from the starting point.