A spinning disk (i.e., a rotating disk) has a radius of 6 cm (6 centimeters) and a constant rate of rotation of 7200 rpm (7200 revolutions per minute). Find the total distance traversed in 5 seconds by a particle of dust that lies at a point on the surface of the disk which is at a distance of 2.5 cm from the center. Express your answer in units of meters.© BrainMass Inc. brainmass.com October 24, 2018, 10:50 pm ad1c9bdddf
The total distance traversed by the particle in 5 seconds is the product of the distance traversed in one revolution of the disk and the number of revolutions that take place in 5 seconds.
Since the time is given in seconds and the rate of rotation is given in units of revolutions per minute, we will express the time (5 seconds) in units of minutes.
There are 60 seconds in 1 minute, so
5 seconds = (5 seconds) X [(1 minute)/(60 seconds)] = (5/60) minutes = (1/12) minute
The number of revolutions of ...
The problem is solved completely, step by step, with a detailed explanation and detailed mathematical computations.
Laminar Boundary Layer Flow Problem
Text Book : Viscous Fluid Flow by Tasos C. Papanastasiou
Download link for the book
8.1. Water approaches an infinitely long and thin plate with uniform velocity.
(a) Determine the velocity distribution ux in the boundary layer given that
ux(x, y) = a(x)y² + b(x)y + c(x) .
(b) What is the flux of mass (per unit length of plate) across the boundary layer?
(c) Calculate the magnitude and the direction of the force needed to keep the plate in place.