I. Draw the velocity diagram for the instant shown and determine the velocity of

Very thin films are usually deposited under vacuum conditions to prevent contamination and ensure that atoms can fly directly fr

katrin [286]

Answer:

a. 9947 m

b. 99476 times

c. 2*10^11 molecules

Explanation:

a) To find the mean free path of the air molecules you use the following formula:

$\lambda=\frac{RT}{\sqrt{2}\pi d^2N_AP}$

R: ideal gas constant = 8.3144 Pam^3/mol K

P: pressure = 1.5*10^{-6} Pa

T: temperature = 300K

N_A: Avogadros' constant = 2.022*10^{23}molecules/mol

d: diameter of the particle = 0.25nm=0.25*10^-9m

By replacing all these values you obtain:

$\lambda=\frac{(8.3144 Pa m^3/mol K)(300K)}{\sqrt{2}\pi (0.25*10^{-9}m)^2(6.02*10^{23})(1.5*10^{-6}Pa)}=9947.62m$

b) If we assume that the molecule, at the average, is at the center of the chamber, the times the molecule will collide is:

$n_{collision}=\frac{9947.62m}{0.05m}\approx198952\ times$

c) By using the equation of the ideal gases you obtain:

$PV=NRT\\\\N=\frac{PV}{RT}=\frac{(1.5*10^{-6}Pa)(\frac{4}{3}\pi(0.05m)^3)}{(8.3144Pa\ m^3/mol\ K)(300K)}=3.14*10^{-13}mol\\\\n=(3.14*10^{-13})(6.02*10^{23})\ molecules\approx2*10^{11}\ molecules$

5 0

3 years ago

Tech a says the higher the numarical gear ratio (4:1), the more torque that will be applied to the wheels. Tech b says that the

Zepler [3.9K]

Answer:

Tech A

Explanation:

The amount of energy required to apply the same force with a 1:1 ratio is divided into 4, so you can apply 4 times as much force than a 1:1 ratio. efficiency and speed come into play here, but assuming the machine powering the gear can run at a unlimited RPM, 4:1 will have more force and a slower output speed than a 2:1 ratio.

3 0

3 years ago

Read 2 more answers

What does STP and NTP stands for in temperature measurement?

Lisa [10]

STP stands for standard temperature pressure and NTP stands for normal temperature pressure

8 0

4 years ago

A specimen of commercially pure copper has a strength of 240 MPa. Estimate its average grain diameter using the Hall-Petch equat

romanna [79]

Answer:

3.115× $10^{-3}$ meter

Explanation:

hall-petch constant for copper is given by

$S_0$ =25 MPa

k=0.12 for copper

now according to hall-petch equation

$S_Y$ = $S_0$ + $\frac{K}{\sqrt{D}}$

240=25+ $\frac{0.12}{\sqrt{D}}$

D=3.115× $10^{-3}$ meter

so the grain diameter using the hall-petch equation=3.115× $10^{-3}$ meter

5 0

3 years ago

What are common metrics used to measure supply chain performance?

Norma-Jean [14]

Answer:

Time, cost and quality.

Explanation:

A supply chain is a network between a company and its suppliers to produce and distribute a specific product to the final buyer, its performance refers to the extended supply chain’s activities in meeting end-customer requirements, including product availability, on-time delivery, and all the necessary inventory and capacity in the supply chain to deliver that performance in a responsive manner. When selecting metrics to measure, there are characteristics that companies should look for, some of these characteristics are the facility to understand it, the relevance of the metric and how easy it is to collect the data obtained.

There are three common supply chain performance metrics:

Time: these metrics are easily calculated and understood, and show operational effectiveness. For example, the level of on-time deliveries and receipts, time to process purchase orders, and time to fulfill an order.
Cost: this metric shows how efficient parts of the company are, they can identify where improvements can be made. Inventory carrying costs is a popular performance metric that helps companies to understand how much it costs them to carry items in the warehouse.

Quality: this metric helps improve customer satisfaction.

I hope you find this information useful and interesting! Good luck!

6 0

3 years ago