JEE Mains Model Paper 5

Typical salt (hard mud) particle of radius 20 mm is on the top of lake water, itsdensity is 2000 kg /m3 and the viscosity of lake water is 1.0 m Pa-s, density is1000 kg /m3 . If the lake is still (has no internal fluid motion), the terminal speedwith which the particle hits the bottom of the lake is ......... mm/s.