A train goes forward at a speed of 1 m/3 for 20 seconds. then it stop and goes backward at a speed of 0.5 m/s?

Question

for 4 seconds after both movements are completed.how far is the train located from its starting point.(note we are asking for the trains final location,not the total distance that is traveled)

choices 18m,19m,20m,22,

Answer 1

1 m/3 ? or 1 m/s ?

If it is 1 m/s for 20 seconds, the train is 18m from it's starting point.

Answer 2

Ok, this is a common sense question.

+1m/sec * 20 sec = 20 meters (positive for forward)

-0.5m/sec * 4 sec = -2 meters (negative because it's backward)

Distance from it's starting point = 20-2 = 18 meters

This ASSUMES instantaneous braking in both directions, we all know what happens when assumptions are made...

Answer 3

Take your Mathematics question over here...http://answers.yahoo.com/dir/;_ylt=Ao5Mu...

Here we do applied physics, and we do it in feet and miles, so take the Metric system with you :)