Physics: How can the motion of an object that is not moving change? an object that is not already moving can . .plz someone

How can the motion of an object that is not moving

Ответ:

sk9600930

18.08.2021

The question is incomplete. The complete question is :

A spherical piece of candy is suspended in flowing water. The candy has a density of 1950 kg/m3 and has a 1.0 cm diameter. The water velocity is 1.0 m/s, the water density is assumed to be 1000.0 kg/m3, and the water viscosity is 1.0x10-3 kg/m/s. The diffusion coefficient of the candy solute in water is 2.0x10-9 m2/s, and the solubility of the candy solute in water is 2.0 kg/m3. Calculate the mass transfer coefficient (m/s) and the dissolution rate (kg/s).

Solution :

From flow over sphere, the mass transfer equation can be written as :

$Sh = 2 + 0.6 Re^{1/2} Sc^{1/3}$

where, Sherood number, $Sh = \frac{K_L d}{D_{eff}}$

Reynolds number, $Re=\frac{Vd\rho}{\mu}$

Schmid number, $Sc= \frac{\mu}{\rho D_{eff}}$

So,

$\frac{K_L d}{D_{eff}}=2+0.6 \left( \frac{V d \rho}{\mu} \right)^{1/2} \ \left( \frac{\mu}{\rho D_{eff}} \right)^{1/3}$

Diameter, d = 1 cm = $1 \times 10^{-2}$ m

V = 1 m/s

$\rho = 1000 \ kg/m^3$

$\mu = 10^{-3} \ kg/m/s$

$D_{eff} = 2 \times 10^{-9} \ m^2/s$

$\frac{K_L \times 10^{-2}}{2 \times 10^{-9}}=2+0.6 \left( \frac{1 \times 10^{-2} \times 10^3}{10^{-3}} \right)^{1/2} \ \left( \frac{10^{-3}}{10^3 \times 2 \times 10^{-9}} \right)^{1/3}$