Tuesday

February 28, 2017
Total # Posts: 29,464

**interesting perhaps relevant**

I just ran into a story about Neanderthals in Europe which might be relevant :) I hope others can open it: http://blogs.discovermagazine.com/crux/2017/01/24/neanderthals-underrated-genius/?utm_source=SilverpopMailing&utm_medium=email&utm_campaign=News0_DSC_170126_000000_Final%...

*January 26, 2017*

**earlier discussion**

http://www.jiskha.com/display.cgi?id=1485466841#1485466841.1485473989

*January 26, 2017*

**Needs attention from Social Science teacher**

I tried but not my thing :)

*January 26, 2017*

**social**

link: http://www.cartoonstock.com/directory/a/amercians.asp I think you are doing fine with it. The immigrant Europeans are assuming that because they have gunpowder they are more important and valuable. They offer the locals something of no value in return for centuries of ...

*January 26, 2017*

**Physics-Momentum**

initial momentum = 1500*15+2500*9 final momentum = -1500*2 + 2500 x initial = final :) 15*15+25*9 = 25x - 30 25 x = 225+30+225 = 480 x = 19.2 =============== check 45,000 = 45,000 ok

*January 26, 2017*

**Math**

20 inches/305 feet = 20 inches/3660 inches = 1 inch/183 inches or 1 inch/15.25 ft

*January 26, 2017*

**Trig**

You mean for the slope of that line? y = -4x slope = -4 in quadrant 2 x = -1 y = 4 hypotenuse = sqrt(17) sin = 4/sqrt17 cos = -1/sqrt17 tan =-4 in quadrant 4 x = 1 y=-4 h = sqrt 17 again sin = -4/sqrt17 cos = 1/sqrt17 tan = -4 again

*January 26, 2017*

**Math**

easier to factor top and bottom that way

*January 26, 2017*

**Math**

That is why I wrote 45 not 4.5 and 2700

*January 26, 2017*

**Math**

45 inches/2700 miles = .01666.....inch/mile or 5 inches/300 miles or 1 inch / 6 miles :)

*January 26, 2017*

**math**

8x + 24 = 8(x+3)

*January 26, 2017*

**Trig**

1/cos T = -5 cos T = -1/5 = -0.20 the absolute value is between 0 and 1 so sure, in quadrant two or three about 101 degrees or 360-101 =259 degrees

*January 26, 2017*

**Evaluating algebraic expressions**

Hey, draw number lines !

*January 26, 2017*

**Evaluating algebraic expressions**

http://www.jiskha.com/display.cgi?id=1485468814

*January 26, 2017*

**Evaluating algebraic expressions**

46 > 42 46 is to the right of 42 on your number line. if you move left n units from each, 46 - n is still to the right of 42 - n

*January 26, 2017*

**Math**

(4x + 5)(7x + 7) = 28x^2+63x+35 (10x+10)(2x + 6) = 20x^2+80x+60 ---------------subtract---------- 8x^2 -17 x -25 = remaining roof which is (8x-25)(x+1)

*January 26, 2017*

**Math**

she doubled speed so took half the time ! half of 50 minutes is 25 minutes

*January 26, 2017*

**Math please check**

assume you mean: [ f(4)-f(2) ] / (2) f(x) = x(2-x) if x = 4 4(2-4) = -8 if x = 2 2(2-2) = 0 so we have -8/2 = -4

*January 26, 2017*

**social studies political cartoon**

http://www.cartoonstock.com/directory/a/amercians.asp

*January 26, 2017*

**social studies political cartoon**

... and then arrogantly named a sport team after them.

*January 26, 2017*

**math**

coat = .5m+2 remainder = m -.5m-2 = .5m-2 dress = .5(.5m-2) +3 remainder = .5m-2 -.5(.5m-2)-3=4 .5m-2-.25m+1-3 = 4 .25 m -4 = 4 .25 m = 8 m = 32 ================== now try that coat = 16+2 = 18 left with 32-18 = 14 dress = 7+3 = 10 left with 4 whew !!

*January 26, 2017*

**Applied Calculus**

oh, since this is calculus and not physics: d^2h/dt^2 = -9.81 so dh/dt = -9.81 t + constant at t = 0, v = Vi so dh/dt = Vi -9.81 t then h = Vi t -(1/2)9.81 t^2 + constant h = Hi when t = 0 so h = Hi + Vi t -4.9 t^2

*January 26, 2017*

**Applied Calculus**

a. Vi = 5 v = Vi - 9.8 t v = zero at top t = 5/9.81 seconds to top b. h = Hi + Vi t -4.9 t^2 = 25+ 5 t - 4.9 t^2 c. 0 = 25 + 5 t - 4.9 t^2 solve quadratic for t use the positive t the negative t is before you threw it :) d. again v = Vi - 9.81 t v = 5 - 9.81*t use t from part ...

*January 26, 2017*

**Trig**

cot = 1/tan = cos/sin csc = 1/sin so cot = csc*cos cos = sqrt(1-sin^2) cot = 3.589142*sqrt(1-1/3.589142^2) =3.447019 or 3.45

*January 26, 2017*

**physics**

1.38*2pi radians/s = 8.67 8.67^2(.139) = 10.4 m/s^2 or about one g Humm, why not leave it sitting in the collander ?

*January 26, 2017*

**physics**

Va^2/140 =Vb^2/295 Va^2/Vb^2 = 140/295 Va/Vb = sqrt(140/295)

*January 26, 2017*

**physics**

distance = 2 pi r = 2 pi*2660 meters speed v = 2 pi 2660/200 meters/s Ac = v^2/r

*January 26, 2017*

**Algebra 1**

-3x + 2y = +11 +3x - 4y = -19 --------------- add 0 -2 y = -8 y = 4 then -3 x + 8 = 11 3x= -3 x = -1

*January 26, 2017*

**Geography please help**

Usually associated with Buddhism but also is part of Hinduism

*January 26, 2017*

**science**

one mol of H2S for every 2 mols of HCl 2.56/2 =1.28 That assumes of course that you put in plenty of Na2S

*January 26, 2017*

**MATHS**

http://www.purplemath.com/modules/triggrph2.htm

*January 26, 2017*

**Physics**

Gave rough beat frequency response below.

*January 26, 2017*

**Social Studies**

So I guess "mother of waters". They may not have been familiar with the bleak ocean :)

*January 26, 2017*

**Social Studies**

maybe for meaning: http://en.wikipedia.org/wiki/Sarasvati_River

*January 26, 2017*

**Very hard math**

.15*75 = 11.25 sure enough

*January 26, 2017*

**Physics**

Look mainly at the low "beat" frequency. 4sin96pit + 8(sin 100pit +sin99pit) 4 sin96pit +16 sin100pitcos4pit saying 199/2 is about 100 that is about 4 sin 100 pi t [1+ 4cos 2 pi t] the low beat frequency is max when 2 pi t = 0, 2pi, etc min when 2 pi t = pi/2, pi/2...

*January 26, 2017*

**math.......**

distributive property of multiplication price = x tax = 0.05 x which is 5%/100 of x 1 x + .05 x = (1+.05) x = 1.05 x

*January 26, 2017*

**Math (Octants identifying) *emergency***

Like here: http://en.wikipedia.org/wiki/Octant_(solid_geometry)

*January 26, 2017*

**Math (Octants identifying) *emergency***

1,1,1 1,1,-1 1,-1,1 1,-1,1 -1,1,1 -1,1,-1 -1,-1,1 -1,-1,-1 are all in different octants you need the sign of x y and z. They are called octants because there are 8 of them. Draw a picture.

*January 26, 2017*

**physics**

say the water is moving in x direction at 4 km/h say we swim in y direction at 3 km/h then our speed is sqrt (3^2+4^2) = 5 km/h tan angle above x axis is tan theta = 3/4 = .75

*January 26, 2017*

**chemistry**

1200 mg /200 = 6

*January 25, 2017*

**Physics**

if you want the compass angle east of north, it is 90 - that

*January 25, 2017*

**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*