(adsbygoogle = window.adsbygoogle || []).push({}); what is "relativistic mass" and "rest mass"..

as far as i know the rest mass is the mass which measured by an observer who is at rest relative to the object (please correct me if this is not right), if this is right.... what if when the object is travelling at the exactly same velocity of the observer.. does "rest mass" also applies to this situation?

relativistic mass is the mass of an object measured by an observer who is moving relative to the object or the mass of an object moving relative to an observer who is measuring the mass entitled to regard himself as stationary. i mean if this is right, in which way, how can the mass be measured if the object is moving.. ?

i am so confused...

thanks

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# What is relativistic mass and rest mass

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