surface friction drag

21 LETTERS · STARTS WITH S

surface friction drag is a valid 21-letter word worth 31 points in Scrabble and 36 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1U1R1F4A1C3E1F4R1I1C3T1I1O1N1D2R1A1G2

1 + 1 + 1 + 4 + 1 + 3 + 1 + 0 + 4 + 1 + 1 + 3 + 1 + 1 + 1 + 1 + 0 + 2 + 1 + 1 + 2 =31 PTS

DOUBLE WORD → 62TRIPLE WORD → 93

MEANING

What does surface friction drag mean?