Question

An iron ball of radius 0.3 cm falls through a column of oil of density 0.94g/cm3. It is found to attain a terminal velocity of 0.5 cm/s. Determine the viscosity of the oil. Given that the density of iron is 7.8g/cm3.

Answer 1

follow the given attatchment to get your solution

Answer 2

Given:

• The radius of the iron ball = 0.3 cm
• Density of oil = 0.94 $g/cm^3$
• Thermal velocity = 0.5 cm/s
• Density of iron = 7.8 $g/cm^3$

To Find:

• The viscosity of the oil.

Solution:

We already have the formula to find the viscosity of the oil. The formula is given by,

⇒  v = 2(ρ-σ)$r^2$g/9$v_t$   → (1)  

where,

ρ - Density of iron

σ - Density of oil

r - radius

g - gravitational constant

$v_t$ - thermal velocity

On Substituting the values in equation (1) we get,

⇒  v = $\frac{2(7.8-0.94)*(0.3)^2*980}{9*0.5}$

⇒ v = $\frac{2(6.86)*0.09*980}{4.5}$  

⇒ v = $\frac{1210.104}{4.5}$ = 268.912 poise

⇒ v = 268.912 poise.

∴ The viscosity of the oil is 268.912 poise.