Friday

October 9, 2015
Total # Posts: 22,103

**Maths**

120 = 10 * 3 * 2 * 2 180 = 10 * 3 * 3 * 2 190 = 10 * 19 looks like 10
*September 18, 2015*

**hard to do half a problem**

evidently f(x) = 6 - c x^2 - 3 x left of x = 6 but you do not say what your function is to the right of 6 anyway the idea is to find c so that the functions are the same at x = 6
*September 18, 2015*

**Physics - URGENT**

Horizontal problem: u = 23 cos 36 until it stops 20 meters = u t so t = 20 /(23 cos 36) use that t in the vertical problem now vertical problem: Vi = 23 sin 36 initial speed up h = 0 + Vi t - 4.9 t^2
*September 18, 2015*

**r n**

each force is 20? then 20 cos (T/2) + 20 (cos T/2) = 30 cos (T/2) = .75 T/2 = 41.4 T = 82.8 degrees
*September 18, 2015*

**no idea**

w+1 L-3 so what, need more information
*September 18, 2015*

**physics**

d = (1/2)(3)t^2 so t = sqrt [ (2/3)(200)] = sqrt (400/3) =20/sqrt3 = 11.5 seconds v = a t = 3 (11.5) = 34.6 m/s
*September 18, 2015*

**Math**

on a number line, every one of those is to the right of the last one, zero, so zero is the smallest.
*September 18, 2015*

**physics**

Normal force = m g cos 22 = 41 * 9.81 * cos 22 = 373 N Force down slope = m g sin 22 = 151 N time to slide 40 m = 40/3.5 acceleration is zero so friction force = 151 N 373 mu = 151 so mu = 151/373
*September 18, 2015*

**Physics**

Vi = 11 sin 62 V = Vi - 9.81 t at top V = 0 so t = Vi/9.81 h = Vi t - 4.9 t^2
*September 17, 2015*

**Linear Algebra**

Maybe start here: Look at the end, how to prove addition and multiplication by a constant remain in R3 http://www.math.jhu.edu/~nitu/subspace.pdf
*September 17, 2015*

**MATHS - please help**

or 5 y - 3 x + 23 = 0
*September 14, 2015*

**MATHS - please help**

If y+4 = (3/5) (x-1) then 5(y+4) = 3 (x-1) 5 y + 20 = 3 x - 3 5 y = 3 x - 23 y = (3/5) x - 23/5
*September 14, 2015*

**not answered because not clear**

y+4 = (3/5) (x-1) or y+4 = 3/ [ 5(x-1) ] ????
*September 14, 2015*

**Maths**

Circumference = 2 pi r
*September 14, 2015*

**Math**

y = 4(5) - 5 y = 15
*September 14, 2015*

**math**

read x y = (1/4) x - 1 print x , y if x = 8 stop go back and read the next x
*September 14, 2015*

**Math**

prime factors of denominators: 5 = 5 * 1 6 = 2 * 3 * 1 so we need 5 * 2 * 3 * 1 = 30 18/30 and 5/30
*September 14, 2015*

**history - no way**

You do not need a tutor to answer these questions. The answers are surely in your text. If not, Google.
*September 13, 2015*

**Physics**

forces: road pushes forward on tires, there is a limit to how hard depending on torque from drive shaft. wind pushes back on vehicle, force increases as speed increases so net force forward = Froad - Fwind a = (Froad - Fwind) / mass when Froad = Fwind, a is zero if a is 0, v ...
*September 13, 2015*

**permutation & Combination**

10!/[4!(6!)] = 10*9*8*7/(4*3*2) = 5*3*2*7 = 70*3 = 210
*September 13, 2015*

**Calculus**

x^2-c and 3 x + 4 c must be the same on both sides when x = 4 16 - c = 12 + 4 c 4 = 5 c c = 4/5
*September 12, 2015*

**science**

Not only peanuts but many plants fix Nitrogen.
*September 12, 2015*

**phyics**

and if you are Rachel, that is a very different question from the earlier one. speed = distance/time velocity = displacement /time for speed you need a speedometer for velocity you need a speedometer and a compass
*September 12, 2015*

**phyics**

zero distance = 400 displacement = 0 (came back to the same spot)
*September 12, 2015*

**phyics**

A is 9/3 = +3 B is 8/2 = +4 C is -6/2 = -3 D is 25/10 = +2.5 now do it.
*September 12, 2015*

**Math**

4 x = 6 (x-200)
*September 12, 2015*

**physic**

400 m/50 s = 8 m/s
*September 12, 2015*

**huh?**

limit as x goes to what ?
*September 12, 2015*

**Math 9th Grade**

distance = speed * time
*September 12, 2015*

**Physics**

Plug and chug, plug and chug :)
*September 12, 2015*

**Physics**

Ball A Hi and Vi v = Vi - g t h = Hi + Vi t - 4.9 t^2 when t = 12 , h = 0 0 = Hi + 12 Vi -4.9 (144) Hi + 12 Vi = 706 Ball B Vi' = -Vi Hi = Hi v = -Vi - g t 0 = Hi - Vi (7) - 4.9 (49) Hi - 7 Vi = 240 subtract the equations to eliminate Hi 19 Vi = 466 Vi = 24.5 m/s Now a new...
*September 12, 2015*

**Algebra: Avc**

x + y + z = 37 5 x + 10 y + 20 z = 310 y = 2 z ============================= x + 3 z = 37 5 x + 40 z = 310 ============================= 5 x + 15 z = 185 5 x + 40 z = 310 ----------------- subtract -25 z = - 125 z = 5 then y = 2 z = 10 so x + 10 + 5 = 37 x = 22
*September 12, 2015*

**Algebra**

3/8(x=8)+1/8x=-1/2(x-7) multiply by 8 3/(x-8) + 1/x = 4(x-7) multiply by x 3x/(x-8) + 1 = 4x(x-7) multiply by (x-8) 3x + (x-8) = 4x(x-8)(x-7) 3 x + x - 8 = 4x(x^2 - 15 x + 56) 4 x - 8 = 4 x^3 - 60 x^2 + 224 x 4 x^3 - 60 x^2 + 220 x + 8 = 0 x^3 - 15 x^2 + 55 x + 2 = 0 Google ...
*September 12, 2015*

**algebra**

3^(2/7) * 3^(2/7) = 3^(4/7)
*September 12, 2015*

**Pre-calculus**

arc tan of 5/0 might be arc tan 90 degrees ? Draw y value of 5 and x value of almost 0 and look at the angle :)
*September 12, 2015*

**trigonometry**

the reference angle is to the X (or -x) axis for 120 it would be 180 - 120 = 60 degrees above x axis cos 60 = 1/2 cos 120 = -1/2
*September 12, 2015*

**physics relativistic energy**

I agree with this: e=mc^2 m = E/c^2 m = 8*10^13 J / (3.0*10^8 m/s)^2 m= 8.89 * 10 ^-4 kg hmm A gram of mass is a lot of energy.
*September 12, 2015*

**algebra**

x = -3
*September 12, 2015*

**Calculus 1**

If all in one direction, the velocity is the speed. To get speed you need a speedometer. To get velocity you need a speedometer and a compass. If you knew derivatives this would be easy v = df/dt = -1 (t^-2) - 1 = -1/t^2 - 1 for t = 5 v = -1/25 -25/25 = -26/25...
*September 12, 2015*

**Physics**

1000 * 9.8 * 10 = 98,000
*September 12, 2015*

**Physics**

the kinetic energy increased but the potential energy DECREASED
*September 12, 2015*

**Social Sudies please help**

If you guess first you might get help.
*September 11, 2015*

**Math**

I get -1.4973 assuming the angle is in radians If it is in degrees I get 1.9770
*September 11, 2015*

**3rd grade math**

they are the same in the thousands but 8,699 has a 6 in the hundreds where 8,563 only has a 5 in the hundreds so 8,699 is bigger
*September 10, 2015*

**Math**

t6 = t1 + 5 d t2 = t1 + d so t1 +5 d = 3 t1 + 3 d so 2 t1 = 2 d d = t1 t10 = t1 + 9d = 10 d t5 = t1 + 4 d = 5 d lo and behold 10 d/ 5 d = 2
*September 10, 2015*

**Physics**

how far did it fall in 5.28 s? d = 4.9 t^2 = 4.9 (5.28)^2 how fast is it going? Vi = g t = 9.81 * 5.28 now how much shaft is left? y = 156 - d so we have to stop it from Vi to v = 0 in y meters 0 = Vi - a t so t = Vi/a = time to stop y = Vi t - .5 a t^2 y = Vi (Vi/a) - .5 Vi^2...
*September 10, 2015*

**Physics (deriving Keplers 3rd law)**

http://galileo.phys.virginia.edu/classes/152.mf1i.spring02/KeplersLaws.htm
*September 10, 2015*

**Physics**

p = ( n R/V ) T p is PROPORTIONAL to T
*September 10, 2015*

**Chem**

silicon is an element but silicone is not - misspelled or trick question quartz is a chemical compound ( SiO4 ) not an element iodine is an element like other halogens water is H2O, a compound not an element silicon is an element as I said above lead is an element of course Pb
*September 10, 2015*

**Geometry**

3x+6=7x-18 so 4x = 24 so x = 6
*September 10, 2015*

**Chemistry**

The last one is the only one that involves a chemical reaction.
*September 10, 2015*

**Chemistry**

233.356 well is it 230 or 240 ? If less than 235, then 230 235 goes to 240 so 0.00240 1.005 ---> 1.01 ---> 1.0
*September 10, 2015*

**MATH**

c = 98,000 + 12.3 x r = 17.98 x
*September 10, 2015*

**Math**

z/2 = 2 (121) - 21 z/2 = 242 - 21 z/2 = 221 z = 442
*September 10, 2015*

**Science please help**

well, the second one might be control
*September 10, 2015*

**math**

which is the smallest one? (under 50)
*September 10, 2015*

**Calculus**

v = dy/dt = 34 - 32 t if t = 1 v = 2
*September 10, 2015*

**Math**

10 in the ones column * 9 in the tens column * 7 in the hundreds column if 0 not allowed 90*7 = 630 ?
*September 10, 2015*

**Math**

permutations = 7!/4! = 7*6*5 = 210 but does beginning with 0 count like 012 ?
*September 10, 2015*

**maths**

slope = [ 7 - (-8)] / [ 2 - (-3) ] = 15/5 = 3
*September 10, 2015*

**Pre-Calculus**

width = w height of rectangle = (3w+1) area of rectangle = 3 w^2 + w area of semicircle = (pi/2) r^2 =(pi/2)w^2/4 = pi w^2/8 total A = (3 + pi/8)w^2 + w
*September 10, 2015*

**Physics**

average speed during stop = 12/2 = 6 v = Vi - a t 0 = 12 - 3 t to stop (get v = 0) so t = 12/3 = 4 seconds to stop distance = average speed * time = 6 * 4 = 24 meters
*September 10, 2015*

**physics**

This question is very misleading because in fact free diving with a snorkel you can go down many, many meters. However you do not breathe while doing so, but hold your breath and your lungs get smaller compressing the air inside. (Your buoyancy also decreases and the deeper ...
*September 10, 2015*

**Chemistry2**

LOL - well it sure had me flummoxed !
*September 9, 2015*

**Chemistry2**

Huh ? This is a chemical reaction, not a nuclear explosion.
*September 9, 2015*

**CALCULUS -HELP!**

x^3 - x = 0 x (x^2-1) = 0 x (x-1)(x+1) = 0 x = 0 x = 1 x = -1
*September 9, 2015*

**CALCULUS -HELP!**

HUH ? set to 0 15 - 3 x = 0 3 x = 15 x = 5 12 - x^2 = 5*0 = 0 x^2 = 12 x = +/- sqrt 12 = +/- 2 sqrt 3
*September 9, 2015*

**Chem**

salinity is normally how much NaCl Na+ is a cation Cl- is an anion
*September 9, 2015*

**Math algeabra**

somehow you have to have a conversion from metric length to English length for example 2.54 cm = 1 inch
*September 9, 2015*

**Social Studies Native Americans**

Wicked hard drying brick in Seattle ! Tough to live in tepees on that side of the mountains as well. It is also difficult to follow salmon migrations without modern seiners. Well, they had birch and they sure had fish. tobacco, corn and squash,- sounds like New England - ...
*September 9, 2015*

**Science**

" .....affects other kids as well ..." Do girls count as "kids" or only boys and small goats?
*September 9, 2015*

**Physics**

v = a t v = 1.4 * 5.6 that is your constant velocity x1 = (1/2) 1.4 (5.6)^2 that is where you are when you start your glide x2 = x1 + v (9.3) that is where you are at t total = 5.6 + 9.3 = 14.9 avergae speed = x2/14.9
*September 9, 2015*

**Science**

Now wait as minute. You guess first.
*September 9, 2015*

**Science**

What does too little data have to do with ethical bias ?
*September 9, 2015*

**Science**

I gave it to you.
*September 9, 2015*

**Science**

from what I observed I deduced that my hypothesis was correct.
*September 9, 2015*

**Vaal reefs technical high school**

This pretty much has the recipe the way I learned it: http://www.chemistry.wustl.edu/~coursedev/Online%20tutorials/Redox.htm
*September 9, 2015*

**Pre-Calc**

once around is 4 pi/2 twice around is 8 pi/2 so this is twice around plus pi/2 which is pi/2 or 90 degrees I suspect you can do the clockwise one now.
*September 9, 2015*

**Pre-Calc**

anything^0 = 1 cos 0 = 1 so (1/4) (1)(1) = 1/4
*September 9, 2015*

**Physics**

VERTICAL PROBLEM: y = (1/2) 6.3 t^2 = 3.15 (5.3)^2 HORIZONTAL PROBLEM: x = (1/2)1.5 t^2 = .75 (5.3)^2 d = sqrt(x^2+y^2)
*September 9, 2015*

**physical fitness (not homework)**

Is it possible that you are overdoing this ?
*September 9, 2015*

**Steve answered your question**

Scroll down.
*September 9, 2015*

**Physics**

a = (final v - initial v)/time = (0 - 12)/t = -12/t so t = -12/a d = Vi t +(1/2) a t^2 10 = 12 t + (1/2)a t^2 10 = 12(-12/a) + (1/2) a (144/a^2) 10 = -144/a + 72/a 10 a = -72 a = -7.2 m/s^2 ============================== note since velocity vs time is linear, you could use the...
*September 9, 2015*

**physics**

10^5 Pa = 1 bar eo this is 1.03360 bar or 1033.60 millibar
*September 9, 2015*

**Garcia**

but it is a straight line of form y = m x + b where m is the slope = 2 but oh well, we can take the derivative {[+2(3+h)+1] - [+2(3)+1] }/h note + 2 not - [6 + 2 h +1 - 6 -1 ] / h 2 h/h 2
*September 9, 2015*

**PHYSICS**

Hey, I showed you haw to do this long ago.
*September 9, 2015*

**Physics**

calulate speed after falling 4.5 m (1/2) m v^2 = m g h so v = sqrt (2 g h) then v t = 4.4 now try the others
*September 8, 2015*

**Physics**

v = v i - g t st top v = 0 so t = vi/g to top then h = 28 + vi t - 4.9 t^2
*September 8, 2015*

**Physics**

hey look v = Vi - g t h = Hi + vi t - 4.9 t^2 u = horizontal velocity = constant by the way
*September 8, 2015*

**Algebra**

-1 + 2/5 is not 2/5 However 2 + 2/5 IS 2 2/5
*September 8, 2015*

**geometry**

4.0 - 2.8
*September 8, 2015*

**Basic Banking Operations**

700 * 12.25 = 8575
*September 8, 2015*

**english 9**

http://www.kshs.org/kansapedia/mary-elizabeth-lease/12128
*September 8, 2015*

**Physics**

a = v^2/r a' = v^2/(r/2) = 2 v^2/r = 2 a
*September 8, 2015*

**Math**

as x gets big +, y ---> 0 as x gets big -, y----> -0 as x ----> -2 , y------> 0 as x ---> 0 , y ----> oo GRAPH IT !!!!
*September 8, 2015*

**Integrated math 1**

1 3 5 7 9 11 13 15 17 19 21 23 25 27 - **--- **------** ------** ----- ** looks like one out of three odd numbers is divisible by 3 so 1/3
*September 8, 2015*

**english 9**

http://www.infoplease.com/encyclopedia/society/americanization.html
*September 8, 2015*

**MATH-Please Help me**

12/4 = 3 times as much 3 * 3 = 9
*September 7, 2015*

**science!**

2. write a hypothesis for this experiment. my answer: if the students compared the growth of the spanish needle seeds with sunlight to other lights, then sunlight will show the best results. =================================== Are you sure? Sunlight is your control and maybe (...
*September 7, 2015*

**Math**

h = (1/2) g t^2 if using feet g = 32 ft/s^2 or h = 16 t^2 t - (1/4) sqrt h
*September 7, 2015*