# Q & A: deceleration to v=0

Most recent answer: 07/06/2015
Q:
this problem is making my head ache.Lets say that an object is moving at a decelerating speed(-1m/s) starting on 4m/s towards east and stopped after 4 seconds. (There are no friction.)After 4 seconds, the object would have 0 speed, no direction and 0 velocity etc.Question 1 : Is the object a null vector(0 vector) after it completely stops?Question 2 : Since the object was moving toward east and then stopped at 4 seconds, can it be said that the object changed directions when it stopped?I mean, the direction changes : East -> None and The vector changes to a null vector too.Question 3 : The object stopped moving so it doesn't have a direction. So, is a change from east to none make a valid 'directional change'?Sorry for the bad english..... it isn't my native language
- Alex (age 16)
California
A:

First, that deceleration is -1m/s2, not m/s.

1) sure, the velocity vector is 0 at the point you mention.

2) I guess it could be said. But it doesn't matter, since when you said v=0 you already said all there was to say about v.

3) Again, it's just words. You already have a complete description. The words are just decoration.

p.s. Your English is better than that of many of the native English speakers who write in.

Mike W.

(published on 07/06/2015)