Asteel sphere (sg = 7.8) of 13 mm diameter falls at a constant velocity of 0.6 m/s through an oil (sg = 0.90). calculate the viscosity of the oil assuming that the fall occurs in a large tank and that the reynolds number is very small.

1.058 decapoise

Explanation:

The specific gravity of a substance is equal to the density of substance in CGS system and if the specific gravity is multiplied by 1000 then we get the density of substance in MKS system.

Density of steel, ρ = 7800 kg/m^3

density of oil, σ = 900 kg/m^3

v = 0.6 m/s

diameter = 13 mm

radius, r = 6.5 mm

Let η be the coefficient of viscosity.

Use the formula for the terminal velocity

η = 1.058 decapoise

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

read more on -

i believe the answer would be:

d. violin, clarinet, french horn, and tuba