# Objects and stationary observers

#### Dx

Hiya!

An object moves in a direction parallel to its length with a velocity that approaches the velocity of light. The width and length of this object, as measured by a stationary observer is what?

Can anyone gimme more insight on this problem. Im having difficulties understanding just what the hell they are talking about.
does the width approach zero while the length approaches infinity.
Dx [zz)]

Related Introductory Physics Homework Help News on Phys.org

#### STAii

Only the dimension in which motion is will change, that is length.
It will get smaller by the factor Sqrt(1-(v2/c2)).
So :
Lseen by observer=Loriginal*sqrt(1-(v2/c2))

Of course, if you wait for an expert to confirm this it would be better.

#### Dx

Ok! Just to make sure I am on the right track then. The width does not change but the length approaches zero because a length of an object is measured to be shorter when its moving relative to the observer than at rest.

Yeah? I think I finally got it.

Dx

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving