Question

The velocity of a small ball of mass 0.3 g and density 8 g/cc when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is 1.3 g/cc, then the value of viscous force acting on the ball will be x × 10^-4 N, and the value of x is ______.

[use g = 10 m/s²]

Options

• 21

• 22

• 24

• 25

Answer 1

The velocity of a small ball of mass 0.3 g and density 8 g/cc when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is 1.3 g/cc, then the value of viscous force acting on the ball will be x × 10^-4 N, and the value of x is 25.

Explanation:

F_v + F_B = mg (V = constant)

F_v = mg - F_B = ρ_B Vg - ρ_L Vg = (ρ_B - ρ_L)Vg

= `(8 - 1.3) xx 10^{+3} xx (0.3 xx 10^-3)/(8 xx 10^3) xx 10 = 25 xx 10^-4` N