Jul 21

the following measurements represent the wind chill as a function of the air speed(wind velocity) at an ambient temperature of 15 degrees F:

wind speed(x)
5,10,,15,20,25,30,35
wind chill T(degrees F)
7,3,0,-2,-4,-5,-7

a. fit a logarithmic equation model(y=a+b in x)
b. use your model to predict the wind chill temperature if the wind speed is 23(ambient T=15 degrees)

a. logarithmic model

a = 18.92076019
b = -7.09634239

x y a+b*ln(a)
577.65
1032.8
150-0.04
20-2-2.05
25-4-3.61
30-5-4.89
35-7-5.97

b. prediction
23-3.03

Jul 4

The construction of a flat rectangular roof (5.6 m x 6.1 m) allows it to withstand a maximum net outward force that is 21,600 N. The density of the air is 1.29 kg/m3. At what wind speed will this roof blow outward?
m/s

v = sqrt(2*lift/(area*rho)) = 31.3103618871671 m/s

Apr 22

Can someone tell me if I got these right?

1. The footprints of a dinosaur are an example of what type of fossil? (1 point)
unaltered remains
mold
carbonized remains
(x) trace fossil

2. Differences in ocean-surface height can be measured by ____. (1 point)

(x) sonar
satellites
submersibles
none of the above

3. Which of the following is associated with mid-ocean ridges? (1 point)
(x) rift valleys
mountainous topography
extreme temperatures
volcanic structures

4. Which regions are thought to be the most level places on Earth? (1 point)
(x) mid-ocean ridges
abyssal plains
deep-ocean trenches
continental slopes

5. Where does seafloor spreading occur? (1 point)
(x) at convergent plates
on seamounts
near the ocean surface
at divergent plates

6. Biogenous sediment is made up of ____. (1 point)
(x) minerals from land
shells and skeletons of marine organisms
minerals from the ocean
evaporative salts

7. The highest salinity would be found in which of the following areas? (1 point)
an area with high rates of precipitation
an area with high rates of evaporation
an area with plenty of runoff
(x) all of the above

8. Where would you find the lowest density seawater? (1 point)
surface mixed zone
transition zone
(x) deep zone
abyssal zone

9. According to the conveyor belt model of ocean circulation, what happens when water reaches the poles? (1 point)
The salinity of the water increases.
(x) The salinity of the water decreases.
The density of the water decreases.
The temperature of the water increases.

10. Which of the following is NOT true about a wave in the open ocean? (1 point)
Water particles move in a circular path.
(x) The wave form moves forward, but the water particles do not advance appreciably.
Water particles travel with the wave.
As the wave travels, water particles pass the energy along by moving in a circle.

11. When is the daily tidal range greatest? (1 point)
spring tide
ebb tide
neap tide
(x) flood tide

12. Which of the following structures is built to protect boats from large breaking waves? (1 point)
jetty
groin
breakwater
(x) seawall

13. Which of the following is true about equinoxes? (1 point)
(x) They occur in June and December.
The sun’s vertical rays are striking either 23.5° S or 23.5° N.
Days and nights are equal in length everywhere.
The length of daylight in the Arctic and Antarctic Circles is 24 hours.

14. Earth receives energy from the sun through what method of heat transfer? (1 point)
conduction
convection
(x) radiation
none of the above

15. Which of the following best describes the temperatures of a city located along a windward coast? (1 point)
warmer summer temperatures than an inland location at the same latitude
(x) cooler summer temperatures than an inland location at the same latitude
summer temperatures that are very similar to an inland location at the same latitude
winter temperatures that are less mild than an inland location at the same latitude

16. Isotherms are lines that connect points of equal ____. (1 point)
latitude
(x) temperature
elevation
pressure

17. A cold, dry air mass that moves over warm, tropical waters will likely become ____. (1 point)
colder and drier
(x) warmer and drier
colder and wetter
warmer and wetter

18. A cT air mass is ____. (1 point)
cold and dry
(x) cold and wet
hot and dry
hot and wet

19. Which of the following is considered to be a boundary between two different air masses? (1 point)
warm front
cold front
(x) both warm front and cold front
neither warm front nor cold front

20. Which stage happens first in the life cycle of a middle-latitude cyclone? (1 point)
Occlusion begins.
A front forms.
Wave shape forms.
(x) Air flows counterclockwise.

21. Thunderstorms form when warm, humid air rises in a(n) ____. (1 point)
unstable environment
stable environment
clockwise spiral
(x) counterclockwise spiral

22. What happens to the intensity of solar energy as latitude increases? (1 point)
It stays the same.
(x) It increases.
It decreases.
It doubles.

23. Global winds move warm air toward the ____. (1 point)
equator
oceans
atmosphere
(x) poles

24. Which of the following is NOT a principal group in the Köppen system? (1 point)
(x) polar climate
dry climate
west coast climate
humid tropical climate

25. In dry climates, rates of evaporation exceed ____. (1 point)
rates of condensation
(x) rates of precipitation
number of sunny days
average temperatures

26. What is the relationship between fossil fuels and the greenhouse effect? (1 point)
Burning fossil fuels decreases incoming solar radiation.
Burning fossil fuels decreases the absorption capacity of greenhouse gases.
Burning fossil fuels lowers the greenhouse effect.
(x) Burning fossil fuels releases carbon dioxide into the atmosphere.

27. The geocen

4/
Mid ocean ridges are actually sloped, highest in the middle and then they plane out the further away you get.
5/
Sea floor spreading occurs are divergent margins (ie plates moving away from each other… spreading). Convergent margins are plates ramming into each other.
17/
wouldn’t it become warmer and wetter?
21/
unstable environment. Conditional instability is the situation needed for thunderstorms. It really doesn’t matter which direction, especially taking into account the northern/southern hemisphere differences.
22/
As you get closer to the poles, intensity of sunlight decreases on average.

Apr 16

Pyro goes off as Click click boom goes off as ScarFace walks to the ring.
ScarFace: First of all,Icon and Chaos have left WWC over some things so tonight we only have 4 competitors left,and as request of CMPV2,your Champion,there will be a Ultimate X Match tonight,and whoever wins,is number 1 contender to the WWC title for Tap or Snap on Sunday.And Finally, After 2 Weeks,Thank you Shawn.

Match 1,Paparazzi ambition vs Cameron hart vs Phenom in a Steel cage elimination match,as whoever is last to get out/pin someone will not face the other 2 in a Submission Match this Sunday.
Match starts with Paparazzi running at Phenom,who throws her into the cage,skull first but then as she turned around,Cameron goes fro a Roll up,but Phenom does a legdrop to reverse as she throws Paparazzi on cameron.Then as Phenom was about to leave,Cameron hits her behind the head with part of the cage she tore off.Then Cameron hits a Missle Dropkick,followed by a Attempted Bit*h Clamp,but Phenom throws her over to Paparazzi who hits a DDT,like a DWI. Then as Phenom was climbing the cage,Pparazzi climbs it to,and both are fighting on the top before Cameron comes by and trys to get both down,butt Phenom gets both of them and hits a Double Chokeslam off the Cage,Through the floor,but with this,Paparazzi and Cameron crawled out the cage,wining the match.
Winners,Paparazzi Ambition and Cameron hart

ScarFace comes out and Announces that CMPV2 will have a match tonight against Malik Hardy and to Ensure nothing Cheap Happens,he announces himself Special Refree

Next match,CMPV2 vs Malik hardy w/ Scarface as Special Referee
Match starts ith some Technical Wrestling,before Malik throws CMPV2 into the top turnbuckle,groin first,Followed by a Attempted Super Back suplex,but CMPV2 throws him to the ground as he goes for a 360 Splash,Malik moves out the way,but CMPV2 landed on his feet and he locks in a Coat to Harms but Malik doesn’t tap as he tosses CMPV2 to the outside,followed by a Suicide dive by Malik,but CMPV2 Catches him and Powerslams Malik through the Table,but both men get in at 8 1/2.Then CMPV2 hits a russian legsweep,followed by a Standing 360 splash,followed by a Pin,1…..2….Kickout!! CMPV2 then goes for a Skull Breaker,but Malik throws him off and he does a Springboad Hurricanrana,but CMPV2 catches him into a Sitout Poweromb,but only gets a 2 count.Then as CMPV2 throws Malik into the corner,he rebounds into a Whisper in the wind,but CMPV2 hits a Clothesline in mid air as he taunts the Crowd.Then he locks in a Figure 4 leglock on the ringpost,but he lets go at 4 as he gets in ScarFace’s face for not letting him keep doing it,then ScarFace slaps him as he tells CMPV2 if he touches Scarface,he will lose the Title to Malik.Then right as CMPV2 turns around,Malik hits him in the face with the Ring bell,as Scarface calls for a DQ.Right after,Malike Grabs CMPV2 and beats him down with the bell,followed by a Cross Rhodes attempt on the bell,but CMPV2 DDT’s him no the bell as he runs off
Winner via DQ,CMPV2

Promo by Risky

Risky Business vs Kawajai vs King Cliff vs Dead as Dawn in a Ultimate X for a WWC title Shot Next sunday at Tap or Snap
Match starts with Kawajai climbing up,but Dawn throws him into the concrete at ringside as he climbs,but Risky trys to pull him down,but Cliff grabs Risky and powerbombs risky and Dawn together to ringside as cliff climbs to grab the X,but Glass Shatters by Disturbed plays as Stone Cold comes out to announce he will be the enforcer for this match.Cliff almost grabs the X but Kawajai throws steel steps at him,as cliff gets Hung upside down,as Kawajai jumps off the top turnbuckle with a Steel chair as he dropkicks cliff’s skull,causing him to fall neck first.At ringside,Risky Nails Dawn with a TV Monitor,followed by a Fishermn Suplex through the barricade.Then as Risky sees Kawajai climbing to get the X,Risky grabs a TV Camera as its still rolling as he climbs to and they fight on top of the structure,Risky goes to hit him with a Camera,but Kawajai ducks and hits a Guarentee it,but Cliff climbs it to as he brawls with Kawajai on it,but Kawajai goes for a Guarentee it,but Cliff reverses with a Ankle lock on top of the structure,but here comes dead as Dawn,as he Big boots Kawajai,nearly knocking him out,but Rightas all 3 men are fighting,Risky hits a Spear on all 3 men OFF the Structure,THROUGH the Announce Table,causing the crowd to chant "HOLY SHI*" then as Risky gets up and climbs the X he goes to grab the X,but Pyro EXPLODES as you see even Austin is suprised as you see a masked person AGAIN,climb the Structure and starts fighting Risky,but Risky hits a low blow on him and goes to throw him off,but he breaks free of Risky’s Grasp and hits a Superkick on Risky as Risky falls off and the masked person runs away.then Dawn locks in a Cloverleaf on Risky,as Kawajai locks in a K-Stretch,and Cliff locks in a Ankle Lock as Risky taps but Right as the Holds are off,
all 3 men brawl,as Dawn accidentally pushed Cliff into Austin.Then as all 3 are about to climb,Austin pulls Dawn down and Stunner’s Dawn.Then as Kawajai and cliff are brawling,Austin climbs up and grabs Cliff and Stuns him on the Structure.Then Kawajai grabs the X and Wins.
Winner Via X,Kawajai!

After the Match,CMPV2 gets in the Ring and does a Red Hot stunner to Kawajai,and right after,Austin gives CMPV2 a Beer,but CMV2 smashes the Beer over Austin’s head over last week as you see the Masked person come in as he Brawls CMPV2 and he hits a Superkick on him too,ending the show.
Nice,You’ll be here next week Icon

The Miz lives in Morrison’s shadow as John is way more talented and charismatic.

Cool show worth 9/10.

Mar 23

For projectiles, 45° is only necessarily the optimal launch angle if ALL of the following apply – otherwise you have to consider specific cases of the eqns:

- the elevation of launch and landing are both equal => s_y(0) = s_y(t1) (usually taken as reference 0, but it’s irrelevant)

- there are no obstacles to be cleared along the trajectory
(i.e. elevation of the terrain s_y(x) <= 0)

- there is no (or negligible) wind or resistance force (e.g. air resistance) => a_x = 0, a_y = -mg

- there is both correct rifling and the bullet is balanced, so that the projectile does not exhibit precession and yaw off at unreliable angles. (http://en.wikipedia.org/wiki/Rifling)
For a gun, the bullet fits the barrel, the grooves are correctly machined to match it, and the exhaust gases are symmetric (may depend on venting).

- For a weapon, the shooter did not move while shooting.
Not sure if the terrain affects whether recoil forces work.

How many more valid reasons can you suggest?
(Sorry for not clarifying ‘optimal’, the browser has been crashing on me for last 2 hrs.)

45° is only the optimal launch angle to maximize range at the expense of everything else (e.g. accuracy, impact velocity i.e. deadliness).
Obvously if you shoot a gun at 45° you will have little accuracy and the bullet will definitely precess.

I should have said there are (at least) two modes of launching a projectile:

- short-range, where we maximize accuracy and impact speed e.g. guns, rifles

- ballistic: long-range artillery, trebuchets

45 may not be a correct launch angle depending on terrain. if your using a short range round like a mortar you may want to use even more elevation to get over hills, building trees and have the projectile straight down. To be honest its something inever really considered

Mar 21

I will be building a house in the San Juan Islands near Bellingham, WA. What is the best material for a garage door? I’ve heard fiberglass is better resistant to the salt air, but a steel door is stronger. We have strong winds in the 80-100MPH range. This will be a standard 2-car garage. 16′ X 7′ door. Any experience or advice would be greatly appreciated.

I would ask your local building inspector. I would go with re-enforced fiberglass, I do know that if the surface in broken up, something like ripples or raised ridges then the wind won’t affect it any, but if it is flat, even steel doesn’t hold up to the wind. plus fiberglass isn’t so hard on your door opener. If you watch what happens during a hurricane, you will see that large flat surfaces like a sign flat roofs and garage doors fly through the air, because they work like an airplane wing,the air moves across the top and creates lift, if an airplane wing had ridges on it then it would never leave the ground.

Mar 19

fun…action/drama and fantasy….
nice storyline…a little funny…hmm…
has unique powers…
Fun……

i like animes like
bleach
DRAGON BOOSTER!!!
death note
elfen lied
zero no tsukaima
kannazuki no miko
zombie loan
shining tears x wind
fate stay night
elfen lied
busou renkin
air gear
air master
kenichi

and etc…..

they all have unique powers… ^^ each different from another

You should try the Dragonball series because it has all of the above.
www.animekiosk.com
has the entire series in high quality.

Mar 17

Raindrops of mass 5 x 10^-7 Kg fall vertically in still air with a uniform speed of 3m/s.
If such drops are falling when a wind is blowing with a speed of 2m/s, what is the angle which the paths of the drops make with the vertical?

Answer: 33.7 degrees

*How do you solve this when you don’t know which direction the wind is blowing from?
(English is not my mother-tongue.)

The question does not give a wind direction only the velocity
of 2m/s so the question is what angle the path of the drops
make with the vertical,you know the velocity of the rain drop
is 3m/s if you draw a right angle triangle 3 unit down and
2 units horizontal, draw a line to meet that is the hypotenuse
call horizontal line ( b ) vertical line ( a )
Tan A = b / a = 2 / 3 = 0.6666, Tan table 0.6666 = 33 .7 deg
Hope that works out alright

Mar 15

My gun shoots 0.20 gram bb’s at a muzzle velocity of 410 f/s (or 125 m/s). I want to ultimately create a table of distance (m) as the independent variable in increments of 5m, vs. velocity (m/s), so I can see how fast the bb will be traveling upon impact with a target X meters away.

I have a basic understanding of what is happening to the bb. I know that (disregarding gravity and any spin on the bb) wind resistance is the only force acting on the bb once it is fired. To calculate the drag force, I know that you can use this equation:

D = 1/2 * C * A * p * v^2

Where D is the drag force in Newtons, C is the drag coefficient (0.47 for a spherical bb), A is the cross-sectional area of the bb (0.0000281 meters), p is the density of the air (1.293 kg/m^3 at STP), and v is the instantaneous velocity of the bb. When I plug all the known values in to the equation above, it becomes:

D = 0.000008534118 * v^2

So this means that the drag force is dependent on the bb’s velocity at a given time. I just don’t know how to put this all together so I can get a nice Distance vs. Velocity chart. Any ideas/help would be much appreciated. Thanks a lot!

The D is a force which causes a negative acceleration on the bb

Therefore the horizontal velocity changes as the bb moves through the air. It decreases.

To truly solve this you need to apply integral calculus.

using a = dv/dt = D/m

So you have dv/v^2 = (0.000008534118/m)*dt

You integrate to solve this for v as a function of t

Then apply v = dx/dt

So the distance dx = v*dt

Integrate this to find x as a function of t

Now for given a given time you have both velocity and distance

Just set up the table t……..x…….v

for different times

Good Luck

Mar 13

An airplane whose air speed is 620 km/h is supposed to fly in a straight path 35.0 degree north of east. But a steady 95 km/h wind is blowing from the north. In what direction should the plane head?
So if I draw two vectors:

vector 1

y= 620 sin 35 = 507.9
x= 620 cos 35 = 355.6

X Y
355.6 507.9
0 -95

355.6 412.9

Determine theta by using tan-1? Am I any closer to understanding it? I get 49 degrees and that isn’t correct.??
The answer is 42.2 North of East but i dont know how to get that

You’ve assumed that the plane will be traveling at a speed of 620 Km/h
in the direction 35NE.. This can’t be right because of the wind.
that speed is one of the unknowns.

however the airspeed in the unknown direction "theta" will be 620 Km/H.

airplane airspeed
y1 = 620 cos(theta)
x1 = 620 sin(theta)

Note that I used cosine for Y1
since due north —> i.e. 0 deg ===> Y1 = 620 cos(0) = 620.

wind
x2 = 0
y2 = -95. blowing toward the south.

resultant Vt = v1+v2 must be at 35NE

Xt = 620 sin(theta)
Yt = 620 cos(theta) – 95

tan35 = opposite/adjacent = Xt/Yt
Note that I used Xt/Yt since tan(0) is due north when Xt = 0.

Xt = Yt. tan35

Solve for theta.
620 sin(theta) = (620 cos(theta) – 95) . tan35

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