A spherical body of radius r and density falls freely through a viscous liquid having density and viscosity and attains a terminal velocity v0. Estimated maximum error in the quantity is : (Ignore errors associated with , and g, gravitational acceleration)
- 2 [ rr - v0v0 ]
- 2 [ rr + v0v0 ]
- 2 rr + v0v0
- 2 rr - v0v0
Answer
(3) 2 rr + v0v0
Solution
Terminal velocity (Stokes' law): v0 = 2r2( - )g9
= 2r2( - )g9v0
Maximum fractional error (errors always add; , , g exact):
= 2 rr + v0v0
Answer: (3)