Class I Help Homework Chapter 5b Begin Date: 11/13/2017 12:01:00 AM End Date: 11
ID: 1788251 • Letter: C
Question
Class I Help Homework Chapter 5b Begin Date: 11/13/2017 12:01:00 AM End Date: 11/24/2017 11:59:00 PM Due Date: 11/20/2017 11:00:00 PM (20%) Problem 2: Calculate the velocity a spherical rain drop would achieve falling (taking downward as positive) from 5.4 km in the following situations. Randomized Variables h 5.4 km -3.2mm d-1.23 kg/m 50% Part (a) Calculate the velocity in the absence of air drag in m/s 50% Part (b) Calculate the velocity with air drag in m/s. Take the size across of the drop to be 3.2 mm, the density of air to be 1.23 kg/m, the density of water to be 1000 kg/m, the surface area to be r, and the drag coefficient to be 1.0 Grade Summary Deductions Potential 100% 0% cos) sino cotan) atan( ) cosh0 tan) acoso sinh( ) Attempts remaining: 45 6 per attemp detailed view asino acotan( ) tanho cotanh0 0 O Degrees O Radians I give up Hints:-deduction per hint. Hints remaining: Feedback:16 deduction per feedback. All content © 2017 Expert TA. LLCExplanation / Answer
)H = 5.4 km ; l = 3.2 mm ; d = 1.23 kg/m^3
b)We know that terminal velocity is given by:
Vt = sqrt (2 mg/ C rho A)
r = l/2 = 1.6 mm
A = pi r^2 = (1.6 x 10^-3)^2 x 3.14 = 8.04 x 10-6 m^2
rhp = m/v => m = rho V
m = 1000 x 4/3 x 3.14 x (1.6 x 10^-3)^3 = 1.71 x 10^-5 kg
Vt = sqrt (2 x 1.71 x 10^-5 x 9.81/ 1 x 1.23 x 8.04 x 10^-6) = 5.82 m/s
Hence, Vt = 5.82 m/s