If you know the distance an object has traveled in a certain amount of time you can determine

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Asailboat is traveling to the right when a gust of wind causes the boat to accelerate leftward at 2.5m/s2 for 4s. after the wind stops, the sailboat is traveling to the left with a velocity of 3.0m/s.assuming the acceleration from the wind is constant, what was the initial velocity of the sailboat before the gust of wind? answer using a coordinate system where rightward is positive.

The field lines around one end of a bar magnet are shown below based on the diagram, what can you conclude about the pole of the magnet? a.is a south pole because the field hnes spread out from this end b.a north pole because the field lines spread out from this end c.a nouth pole because the field lines enter the magnet at this end d.is a north pole because the field lines enter the magnet at this end