Hi
That's because the D4 goes faster than the TD5. The TD5 might be 1995 kg rest mass but the if the D4 was lighter, say 1900 kg and travels at about 0.64 x c (c=speed of light) then its mass will increase to:
which is 2580 kg. Thus a lighter and faster D4 can appear to be more massive than a defender at rest on the weighbridge.Code:1990 kg
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sqrt(1-v2/c2)
Reference: Mass in special relativity - Wikipedia
Mike

