Impinging air jets may be used to clean particles from surfaces. The kinetic energy per unit volume (J/m3) of an air jet at a surface, Er, may be written as:

E=1/2*(rho*v2)* k*d-1.3

Where:

rho = density of air (1.3 kg/m3),

v = air velocity

k = proportionality constant (0.4 mm 1.3)

d = distance from the jet nozzle (10 mm).

For a sphere (A4 = 1x10-19 J) adhered to a flat surface (A2 = 1x10-20 J), find:

1. What size of particle (diameter) could a hurricane force wind (v = 118 km/h) remove from a

surface?

2. What size of particle can be removed at v = 340 m/s (speed of sound)?

3. What air velocity would be required to remove a 1 mm particle and a 100 nm particle?

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.