# Posts by Damon

Total # Posts: 29,612

**Physics**

North 150 cos 60 = 75 km N East 150 sin 60 - 100 = 29.9 km E distance = sqrt(75^2+29.9^2) tan angle north of east = 75/29.9

*January 25, 2017*

**calculus**

No need for L'Hopital 16-x^2 = (4-x)(4+x) so you really have: (4-x) at x = -4 4-(-4) = 8

*January 25, 2017*

**enough**

You are wasting your time and ours. Please take the course before you try to do the problems.

*January 25, 2017*

**Trigonometry with right triangles**

If you were taking geometry, you would be in serious trouble.

*January 25, 2017*

**Trigonometry with right triangles**

He did not understand my reply to the last question either. He clearly has not studied the material yet.

*January 25, 2017*

**Some basic concept of chemistry**

http://www.lagoonsonline.com/laboratory-articles/normality.htm

*January 25, 2017*

**Physical Sciences**

Google diamond. I think you will find that it is pure Carbon, C. The carbon atoms are arranged in a crystal structure under high temp and pressure.

*January 25, 2017*

**Pseudocode**

20*1.05 = 21 or do it the hard way 20*1 + .05*20 = 20 + 1 = 21 note use of distributive property to do it fast.

*January 25, 2017*

**geometry**

1-s)(1+s) 1-s^2 1-sin^2x = cos^2x cos^2x + cos^2 (sin^2x/cos^2x) = cos^2 x + sin^2 x = 1

*January 25, 2017*

**how far behind?**

truck goes 20 t car goes 50 t 50 t - 20 t = distance behind in kilometers resulting t is in hours multiply by 3600 to get seconds

*January 25, 2017*

**math**

--- 1 2 3 4 5 6 1========1,4 2 =====2,3 3 ==3,2 4=4,1 5 6 four out of 36 = 1/9 that is one out of every nine so a once b twice c three times d 100/9 = about 11 times e 450/9 = 50 times

*January 25, 2017*

**Math!!!!**

You are welcome.

*January 25, 2017*

**Math!!!!**

Well, you do not build each piston for each cylinder. You order the piston from the auto parts store for your type of engine. It better be the same size and shape as the old one or it either will not fit the cylinder or the connecting rod or the piston rings.

*January 25, 2017*

**Math!!!!**

Ah, pistons in your car engine?

*January 25, 2017*

**Math**

links in your bike chain?

*January 25, 2017*

**Geometry/Trig**

tan 80 = 18/x so x = 18/tan 80

*January 25, 2017*

**Dating with Radioactivity**

I am not geologist but question: 3. Upside down? 4. If there is sand in the granite did the sand not already exist when the granite formed? 5. Not at all sure 7. I suspect rapid burial but read your text about it.

*January 25, 2017*

**Geometry / Trig**

well, we need the area of an equilateral triangle with sides of one cm. Then we multiply by six for altitude sin 30 = (1/2)/1 cos 30 = h/1 h=.866 so area of triangle = (1/2)(1)(.866) = .433 then multiply by six 6*.433 = 2.6 cm^2

*January 25, 2017*

**8th grade math /lesson3/functions**

Those are all arithmetic sequences above 7. is correct

*January 25, 2017*

**8th grade math /lesson3/functions**

up TEN each time 39,49,59

*January 25, 2017*

**8th grade math /lesson3/functions**

3*1+5 = 8 3*2+5 = 11 3*3+5 = 14

*January 25, 2017*

**8th grade math /lesson3/functions**

In the first one, subtract 8 each time so -2, -10 , -18

*January 25, 2017*

**math**

0.60 x = 372 so x = 372/0.60 = 3720/6

*January 25, 2017*

**Science**

Way too much H2 H2O = 2 + 16 = 18 grams/mol that is 16 g/mol of O so 8 g is 1/2 mol of O H2 is 2 g/mol so 5g is 2.6 mol, more than we need so we end up with 1/2 mol of water which is 9 grams

*January 25, 2017*

**CHECK answers science**

Yes. I might argue about #3 because Thompson's "plum pudding" model was pretty crude compared to Rutherford's model, but Thomson did have sub atomic particles.

*January 25, 2017*

**error**

last two lines d = 4.9 t^2 = 2.33 meters

*January 24, 2017*

**physics**

average speed passing window = -2 meters/.25 s = -8 ms constant acceleration = -9.81 m/s so while crossing the window v = Vi -.981t change in v while crossing window = -9.81*.25 = -2.4525 m/s half that = -1.23 m/s so v at window top = -8+1.23 = -6.77 m/s so how far did it fall...

*January 24, 2017*

**Physics**

but then 1 second * initial speed + (1/2)(4)t^2

*January 24, 2017*

**Specify a Period on the graph**

see question below this one.

*January 24, 2017*

**Calculus**

when is 5 pi x = 2 pi ???? x = 2/5

*January 24, 2017*

**Math**

8+8 + x+x = 26 2 x = 10 x = 5 but you have a typo no doubt I bet the perimeter is 260 yards.

*January 24, 2017*

**physics**

Law #1 momentum of passenger continues forward until acted upon by windshield or other force.

*January 24, 2017*

**physics**

Well, lots of things can happen but what you can count on is conservation of momentum of the overall runner, tackler, ground system. Any forces from the ground on the people can change the momentum of the merged runner-tackler system. If they were both on ice and ran into each...

*January 24, 2017*

**Math**

4 2/3 = 14/3 divide by 5 14/15

*January 24, 2017*

**Calculus**

If it is a horizontal line the slope is zero. y = a constant (y-y1)/(x-x1) = 0 y - y1 = 0 y = y1 put in the given y y = -9

*January 24, 2017*

**Yoruba**

If you just want the word for sun: http://www.wordhippo.com/what-is/the/yoruba-word-for-22fa6121da96f43a106e413e65d4f9089c53824c.html

*January 23, 2017*

**Geometry**

http://www.calculatorsoup.com/calculators/geometry-solids/cone.php

*January 23, 2017*

**Geometry**

do not do that Lillylove volume of sphere = (4/3)pi r^3

*January 23, 2017*

**School**

oh my, schools, unions, Planned Parenthood .....

*January 23, 2017*

**School**

Yes, I bet she was very busy. http://democracywise.syr.edu/?p=3939

*January 23, 2017*

**School**

I do not see anything written about her in the last couple of days, but judging by her history in government I bet she had a very busy weekend, perhaps in Washington.

*January 23, 2017*

**School**

Councilor at large, Syracuse, NY ? Google her name

*January 23, 2017*

**Math**

You are welcome.

*January 23, 2017*

**Math**

60% of them :) .6*70 = 6*7 = 42

*January 23, 2017*

**algebra**

should look like 11 x^2 - 28 x -480 = 0 (11x+60)(x-8) = 0

*January 23, 2017*

**you try first**

This time you try first and show work. Same method.

*January 23, 2017*

**math**

aaarrrrggh too many of these, use: http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

*January 23, 2017*

**author?**

Try to google story "knife" LOL

*January 23, 2017*

**math**

straight up and down, (Y2-Y1)/(x2-x1) = (Y2-Y1)/ 0 undefined

*January 23, 2017*

**math**

compounds 24 times a year so r = .03/24 = 0.00125 per period 25 years = 25*24 = 600 periods A = 10,000 * 1.00125^600 = 10,000 * 2.116008731 = $21,160.09

*January 23, 2017*

**Science**

6 volt battery resistance of 8 ohms I assume the resistors are also in series i = 6/8 = 3/4 = 0.75 amps

*January 23, 2017*

**algebra**

x^2 + (x+6)^2 = (x+12)^2 x^2+ x^2+ 12 x + 36 = x^2 +24 x +144 x^2 - 12 x - 108 = 0 108 is 6*18 for example (x-18)(x+6) = 0 try x = 18 then x+6 = 24 and x+12 = 30 ===================== check 18^2 + 24^2 = 30^2 ???????? 324 + 576 = 900 whew !

*January 23, 2017*

**Ethics**

Actually from a maximum utility benefit/cost point of view, I should think B would be the winner.

*January 23, 2017*

**Geometry**

length scale = 4/17 area scale = 4^2/17^2 = 16/289 vol scale = 4^3/17^3 = 64/4913 x^3/y^3 = 1728/343 volume ratio x^2/y^2 = 576/y^2 area ratio x/y =(1728/343)^(1/3) = 5.0379^(1/3) = 1.7143 length ratio so x^2/y^2 = 1.7143^2 = 2.939 so 2.939 = 576/y^2 y^2 = 196 meters^2

*January 23, 2017*

**Geometry help**

You are welcome.

*January 23, 2017*

**Geometry help**

for anything with a pointed top and straight sides the volume = area of base * height *(1/3) so here the side^2*h is the same for each 14^2*24 = s^2*96 or 14^2/s^2 = 4 14/s = 2 s = 7

*January 23, 2017*

**Geometry help**

12*12*(9/12) = 108 ft^3 there are 3*3*3 = 27 ft^3/yd^3 108/27 = 4 cubic yards 4*54 = $216

*January 23, 2017*

**Chemistry**

Did the vapor pressure of this liquid change when you squeezed the gas down? I think not. Therefore the pressure did not change. You have half as many gas molecules above the fluid. Half the gas molecules condensed back into liquid form.

*January 23, 2017*

**HELP PLEASE**

Yes, exactly.

*January 23, 2017*

**Calculus**

f(3) = 0 f(0) = 9 slope = (0-9)/3 = -3 f' = -2x where is -2x = -3 ? x = 1.5

*January 22, 2017*

**Chemistry**

volume = 2.3 ml mass = 1.0107*10^-2 kg =10.107 grams density= m/v =10.107/2.3 = 4.39 g/mL maybe Titanium ?

*January 22, 2017*

**Chem**

3 * .25 * 6 * 10^23

*January 22, 2017*

**Chem**

You need 3 mol of A for every mol of B but you only have 2 mol A so you only use 2/3 of a mol of B that would yield 4/3 mol of C but we only got 1 mol of C 100 * 1/(4/3) = 75 % yield

*January 22, 2017*

**Math**

Take the average speed during each second times one second and add 6+9+8+7.5+10.5+8.5+6.5+9+8+9 = 82

*January 22, 2017*

**Chemistry**

grams/mol N=14 H=1 F= 19 so NH3 =17 F2 = 38 HF = 20 so If I have 4 g of NH3, how many g of F2 do I need? 4/[2(17)] = x/[5(38)] x = 20*38/34 = 22.4 g F2 whoops, not enough F2 so use 14 of F2 and y of NH3 y/34 = 14/190 y = 2.5 grams of NH3 then 2.5/34 = HF/[6(20)] HF = 8.82 ...

*January 22, 2017*

**pre algebra**

168 miles/3.5 hours = 48 mi/h

*January 22, 2017*

**Chemistry**

See below, I got 500

*January 22, 2017*

**Chemistry**

P V = n R T n is number of mols say we have 1 mol (n=1) of argon, 40 grams then we have 40 grams of Methane which is 40/16 or 2.5 mols (n=2.5) they both have the same V and T P/n = RT/V = same for each 200/1 = Pmeth/2.5 Pmeth = 2.5*200 = 500 torr

*January 22, 2017*

**Chem 112**

Zn = 65.4 grams/mol Cl = 35.5 grams/mol H = 1 gram/mol so 2HCl = 2(36.5g/mol) = 73 g ZnCl2 = 136.4 g/mol to get 1 gram ZnCl2 need (1/.684)(65.4/136.4)= .701 grams Zn

*January 22, 2017*

**Math**

original height = H h(t) = height dh/dt = -2cm/20min = -0.1 cm/min so h = H - 0.1 t h in cm, t in minutes

*January 22, 2017*

**phyisics**

You mean it stopped after 8 meters? If so average speed = (3+0)/2 = 1.5 m/s so t = 8/1.5 = 80/15 = 5.33 seconds sliding to a stop then acceleration a = (0-3)/5.33 = -.5625 m/s^2 so now the physics F = m a -m g (mu) = m (-.5625) mu = .5625/9.81 = .0573

*January 22, 2017*

**Calculus**

df/dx = -3 df = -3 dx |.05| = -3 |dx| |dx| = .01667 check if x = 1.01667 f(x) = -3(1.01667) + 2 = -3.05+ 2 = -1.05 distance from -1 is .05 sure enough

*January 22, 2017*

**chemistry**

answered this below

*January 22, 2017*

**chemistry**

2Mg + O2 ---> 2 MgO Mg = 24.3 g/mol O = 16 g/mol so 48.6 grams Mg + 32 grams O2 --> 80.6 grams MgO 5/80.6 = .062 mol MgO produced x/32 = .062 x = 1.985 grams O2 and we needed y/48.6 = .062 y = 3.00 grams of Mg sure enough

*January 22, 2017*

**chemistry**

if the masses are equal, the diamond has more volume because it is less dense.

*January 22, 2017*

**Math**

well, let's try the 20 on the bottom and the 15 sloping up toward the right. Try the diagonal connecting the two right ends. draw altitude h that divides the base into x and (20-x) x^2+ h^2 = 225 so h^2 = 225-x^2 (20-x)^2 + h^2 = 625 ----------------------- 400 -40 x + x^2...

*January 22, 2017*

**science**

original momentum = .04*500 = 20 kg m/s that will be the final momentum so 6 v + .04*200 = .04*500 6 v = .04*300 v = .04*50 v = 2 m/s

*January 22, 2017*

**Science**

Probably very hungry. They might not recognize the orchids as food. Many might die. I do not know anything about the relative nutritional value of cactus and orchid flowers. That would determine if a low surviving population would continue feeding on the few cactus plants or ...

*January 22, 2017*

**Finite math**

5 c + 7 s + 9 a = 6100 c + s + a = 900 a = .5 (c+s) or 2a - c - s = 0 ============================ add two and three 3 a = 900 so a = 300 c+s = 600 so s = 600 - c 3 c + 7 s + 2700 = 6100 3 c + 7(600-c) = 3400 3 c + 4200 - 7 c = 3400 4 c = 800 c = 200

*January 22, 2017*

**Physics 20**

No, the asteroid does NOT have a mass of 2.71 kg. That would be about the mass of a gallon or so of milk. I said 2.71*10^20 kg

*January 21, 2017*

**Physics 20**

READ A is 7620 m/s B is 2.71*10^20 kg

*January 21, 2017*

**Physics 20**

A is 7620 m/s B is 2.71*10^20 kg and for heaven's sake use SCI units, do not use km and hours or something. Use meters, seconds, Newtons, kilograms. 1 hour = 3600 seconds 1 km = 1000 meters

*January 21, 2017*

**Physics 20**

B) v(9.06*10^3) = 2 pi (311) v = .216 m/s I do not think so, suspect you mean 311km not 311 m that would give v = 216 m/s then 7620^2 = G Ma/r 7620^2 = 6.67*10^-11 Ma/311 Ma = 2.71*10^20 kg

*January 21, 2017*

**Physics 20**

v^2 = G Me/r v^2 = (6.67*10^-11)(5.97*10^24) /6.85*10^6 v^2 = 5.81 * 10^7 = 58.1*10^6 so v = 7.62*10^3 so v = 7620 meters/second

*January 21, 2017*

**Physics 20**

A)when in orbit about earth mv^2/r = m (G Mearth)/r^2 solve for v B) same equation but get v immediately v T = 2 pi r then m v^2/r = m Ma(G/r^2) m , mass of sat cancels we know v solve for Ma

*January 21, 2017*

**Physics 20**

I did B

*January 21, 2017*

**Physics 20**

Weight is NOT in kg but in Newtons !!!!!! F = m * 9.81 = 154*9.81 = 1510 Newtons

*January 21, 2017*

**Physics 20**

A) F = G m Me /r^2 at surface G Me/r^2 = 9.81 B) answer to A*r^2/(r+222,000)^2 but if you try to measure it with a scale, zero because F is balanced exactly by mv^2/R if in orbit which is the answer to part C. Really weight in orbit means nothing.

*January 21, 2017*

**Physic**

x = 1.6 (pi)cos(pi*1.3 +pi/3) = 5.03 cos (1.63 pi) = 5.03 * .397

*January 21, 2017*

**Algebra**

(A/2) -5 = 35 A/2 = 40 A = 80

*January 21, 2017*

**Health**

yes. Despite the act that it ends in s, it is one disease.

*January 21, 2017*

**Physics 20 Energy**

m g (change in height) 85 * 9.81 * 2.4 *1000 Joules

*January 21, 2017*

**Physics 20**

5(2.5)^2 =5*6.25

*January 21, 2017*

**huh??**

It is a four dimensional pool?

*January 21, 2017*

**Chemistry**

H2O = 18 g/mol so I have 5.5/18 mols water you get two mols H2O for every mol of O2 so I used 5.5/36 mols O2 O2 = 32 g/mol so 5.5*32/36 = 4.89 grams O2

*January 21, 2017*

**Chemistry**

Fe2O3 + Al ---> Al2O3 + Fe same number of mols of Fe as of Al Al = 30 g/mol so 225/30 mols of Al so 225/30 mols of Fe so (225/30) mol mass of Fe (225/30)56 = 420 grams of iron

*January 21, 2017*

**Nope**

Look at it on a number line. for positive x-3 x must be to the right of 3 but then sqrt x must be greater than sqrt (x-3) which is not possible. If it were -3 on the right, that would be different (x-3)^.5 - x^.5 = 3 square both sides [(x-3)^.5-x^.5][(x-3)^.5-x^.5] = 9 (x-3)-2...

*January 21, 2017*

**Physics 20 Gravity**

11.2 m/s^2 as compared to 9.81 on earth

*January 21, 2017*

**Physics 20 Gravity**

g = F/m = G M/r^2 where G = 6.67*10^-11 M = 7.66*10^24 r = 6.74*10^6

*January 21, 2017*

**English**

maybe something like: Increased government subsidies would make US manufacturers more competitive with heavily subsidized foreign industries.

*January 21, 2017*