Question

two spherical raindrops of equal size are falling vertically through are with a terminal velocity of 0.1m/s . What would be the terminal velocity of the two drops were to coalesce to form a single spherical d drop?

Answer 1

Here in this always remember that the volume remains constant .
So , 43πR3=n×43πr3⇒R3=8r3⇒R=2r
Now the terminal velocity is directly proportional to the square of the radius .
Therefore V1V2=rR2=r2r2=14⇒V2=4×V1=4×0·1 =0·4 m/s
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