Saturday

November 28, 2015
Total # Posts: 22,925

**Typos, math, physics**

forgot x -.28 * 9.81 * x = (1/2) * (.13^2 - .28^2)
*October 24, 2015*

**physics**

work done = force * distance = change in kinetic energy F = -.28 m g = -.28 * 18 * 9.81 work = F * x final - initial Ke = (1/2) *18 * (.13^2 - .28^2) so -.28 * 9.81 = (1/2) * (.13^2 - .28^2)
*October 24, 2015*

**Physics (Biomechanics)**

weight component down hill = 75*9.81 * sin 30 a = (75*9.81*.5 - 11 -9 )/75
*October 24, 2015*

**Physics**

west wrap right hand fingers around wheel so the top of the tire scrapes your hand from palm to finger tips. Your thumb points left or west. Rotation is clockwise around westward pointing axis.
*October 24, 2015*

**physics**

I do not do magic. I do not have your diagram. Is the monkey falling at the same time you release the banana? If so, then shoot straight at the monkey because the banana and the monkey fall at the same rate. Thus you only need the time for the monkey to fall H h = (1/2) g t^2 ...
*October 24, 2015*

**History**

Sorry - use Ms Sue reply
*October 24, 2015*

**History**

It is an estimate because it is virtually impossible to gather data on every single citizen
*October 24, 2015*

**astronomy**

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/wien3.html
*October 24, 2015*

**astronomy**

well, what is wavelength of visible light? for resolution it is the ratio of wavelength to distance between slots that matters. for your radio it is 1^10^-3 meters / .6*10^ m the lower the wavelength to baseline, the sharper
*October 24, 2015*

**astronomy**

by the way p is pi, 3.14159 etc
*October 24, 2015*

**astronomy**

http://www.schoolphysics.co.uk/age16-19/Mechanics/Gravitation/text/Geostationary_satellite/index.html
*October 24, 2015*

**Physics**

west - right fingers around wheel, thumb points west
*October 24, 2015*

**algebra**

n - 3 = 39 - n 2 n = 42 n = 21
*October 24, 2015*

**math**

well, it does not ask for x but x - 11 = 134 - 2 x - 22 3 x = 123 x = 41
*October 24, 2015*

**math**

C+D = 67 so C = 67 - D (D-11) = 2 (C-11) call D x x-11 = 2(67-x -11)
*October 24, 2015*

**math help azap!!!!!!!!!!!!**

yes, subtract 15 from both sides and you get x = -7
*October 23, 2015*

**math help azap!!!!!!!!!!!!**

8 - 15 = - 7
*October 23, 2015*

**Physics**

v = Vi - g t at top v = 0 so 0 = Vi - 9.81 t Vi = 9.81 t h = Hi + Vi t - 4.9 t^2 but t = Vi/9.81 so 25 = Vi (Vi/9.81) - 4.9 (Vi^2/9.81^2) 25 = Vi^2 (.102 - .051) Vi^2 = 490 Vi = 22.1 alternatively (1/2) m Vi^2 = m g h or Vi = sqrt (2 g h) = 22.14
*October 23, 2015*

**Physics**

Vi = 0 h = initial height - (1/2) g t^2 h = 0 - 4.9 (4) h = - 19.6 metersd it fell 19.6 meters
*October 23, 2015*

**Physics**

Vi = 0.1 v = Vi - 9.81 t h = Vi t - 4.9 t^2 h = 0.1 (1.5) - 4.9 (2.25)
*October 23, 2015*

**Physical Education**

That makes sense. I was not sure if the first one was B or C
*October 23, 2015*

**Physical Education**

Not sure about the first but try: http://www.aging.columbia.edu/sites/default/files/Reitz,%20Zimmerman,%20Hutteman,%20Specht,%20Neyer_in%20press.pdf What is an extrovert? What is your identity?
*October 23, 2015*

**Physical Science-Physics**

It does not mention weight, only asked for m There is no need to use a = 1.54 as the problem is stated. I bet there is a part B though that asks for the average force Then F - m g = m (1.54)
*October 23, 2015*

**Physical Science-Physics**

m g h = gain in potential energy so m (9.81)( .78) = 1.56 or m = 1.56/(9.81*.78) If it asked for the force, you could now do F = m a
*October 23, 2015*

**science**

You have half a period T = 2 pi sqrt (L/g) = 2 pi sqrt (20/9.81) use T/2
*October 23, 2015*

**College Physics**

:)
*October 23, 2015*

**College Physics**

Melissa - your method is correct but numbers are different.
*October 23, 2015*

**College Physics**

momentum = .140 * 7.5 force = change of momentum / time = .140 * 7.5 / .19
*October 23, 2015*

**PLZ Help History--@Ms. Sue**

1. sounds like ther spinning mills in Lowell to me. 2. The stamp act was perhaps the biggest one. 3. Closing Boston led to other American colonies rallying in support. 4. Tories
*October 23, 2015*

**PLZ Help History--@Ms. Sue**

I said B, and Sam Adams
*October 23, 2015*

**PLZ Help History--@Ms. Sue**

Sam Adams objecting to duty on tea.
*October 23, 2015*

**PLZ Help History--@Ms. Sue**

Actually I think Sam Adams and B
*October 23, 2015*

**PLZ Help History--@Ms. Sue**

ah, I would pick the last one. First I heard of Napoleon fighting over here although his troops fought in the West Indies. I suppose one could stretch ones imagination to consider the French already trying to hold on to the Mississippi We had some serious Revolutionary War ...
*October 23, 2015*

**PLZ Help History--@Ms. Sue or @Reed**

Sorry - I think B
*October 23, 2015*

**PLZ Help History--@Ms. Sue or @Reed**

yes
*October 23, 2015*

**math**

for example there are 1000 meters in a kilometer so if you have 6051 meters 6051 m * ( 1 km / 1000 m) = 6.051 km something/the same thing in other units is effectively one. It just changes the units eg 2.35 cm ( 1 m / 100 cm) = .0235 m
*October 23, 2015*

**Urgent Math! Please Help!**

2^-4 = 1/2^4 = 1/16 = 1/2*1/2*1/2*1/2 note x^-y = 1/x^y
*October 23, 2015*

**Physics**

work in = increase in potential energy F (.75/1000) = m g h = 4*10^-6 * 9.81 * .25
*October 22, 2015*

**math - fraction**

25/100 + 14/100 + 54/100 = ?
*October 22, 2015*

**algebra**

if it is as you typed it then r = (a/a) b + b and a can be any real number
*October 22, 2015*

**physics**

Vt = omega * r = 2 * 4 = 8 m/s
*October 22, 2015*

**Calculus III - TYPO**

y = x-1 dy/dx = slope = Hey ! this is not a hyperbola but a straight line = 1 the particle is never at 4,14
*October 22, 2015*

**American History**

or just guess :)
*October 22, 2015*

**Physics**

Use potential energy of one cubic meter of water at 108 m high = 1000 * 9.81 * 108 Joules then cubic meters per second = (1/60)(5.5 * 10 ^8) so Joules per second = Watts power = (9810*108* 5.5 /60)10^8 Watts (a lot!)
*October 22, 2015*

**Square Roots (Math)**

sqrt 49 = 7 sqrt 36 = 6 so almost 7 actually 6.86
*October 22, 2015*

**Calculus**

height = x width = (15-2x) A = x(15-2x) = 15 x - 2 x^2 at max or min dA/dx = 0 = 15 - 4 x so x = 15/4 (wish they had given us 16 :)
*October 22, 2015*

**Help @Damon**

Patriot
*October 21, 2015*

**History @Reed**

You are welcome. By the way look down this screen and check the reply to the Boston tea party question
*October 21, 2015*

**History @Reed**

Well, that would be my choice, but I am only a physicist. I am however from a certain Massachusetts seaport.
*October 21, 2015*

**History @Reed**

Well, your choice, John Adams, defended the British soldiers at trial after the Boston Massacre because he wanted them to have a fair and just trial. I would not call that propaganda. Sam made it out to be sheer mayhem murder.
*October 21, 2015*

**History @Reed**

I think you want the rabble rouser, not the statesman :)
*October 21, 2015*

**History @Reed**

google sam adams
*October 21, 2015*

**Chemistry**

yes yes
*October 21, 2015*

**Chemistry**

CaF2 molar mass = 78.07 check Ca molar mass = 40.1 F2 molar mass = 2*19 = 38 8.4 g calcium is 8.4/40.1 = .2095 mol .2095 mol of CaF2 = 16.35 grams, not 15 grams now part a 30 g * 40.1/78.07 = 15.3
*October 21, 2015*

**chemistry**

313 pounds * .454 kg/pound = 142 kg so burns 142 *10^3 grams/second 142*10^3 g/s * t = 459*10^6 g so t = (459/142)*10^3 seconds 7.03 km/s * (459/142)*10^3 = distance = 22.7 *10^3 = 2.27 *10^4 remarkably choice A
*October 21, 2015*

**Math**

35 is not 4 times 5 4x + x = 40 5 x = 40 x = 8 yellow 4x = 32 blue
*October 21, 2015*

**Chemistry**

well silver usually is found in mines but if you are asking original origin I suppose everything sort of comes from outer space.
*October 21, 2015*

**Math2**

25,000 miles * ( .125 inch/125 miles) = 25 inches
*October 21, 2015*

**Math**

x = miles gas remaining in Beth tank = 15 - x/30 gas remaining in Darcy tank = 16 - x/25 so 15 - x/30 = 16 - x/25 or 1 = x (1/25 - 1/30) 1 = x (.0066666666..... x = 150 miles
*October 21, 2015*

**Chemistry**

P1 V1 = P2 V2 7.1 P1 = 50.2 P1 = 7.07 atm I do not know why it says mL when you are using liters L Anyway the answer is in ATMOSPHERES pressure, not milliliters or Liters
*October 21, 2015*

**math**

distance = speed * time 9 = (v-9) t 20 = (v+9) t but t is the same so 9/(v-9) = 20/(v+9) 9(v+9) = 20(v-9) 9 v + 81 = 20 v - 180 11 v = 261 v = 23.7
*October 21, 2015*

**Math**

16.5 / 10.5 = 1.5714
*October 21, 2015*

**Physics**

.1 * 1000 = 10 v v = 10
*October 21, 2015*

**Need biologist - genetics**

Not my thing, sorry but based on what little I remember that sounds correct.
*October 21, 2015*

**Math**

(1+3i)(1+2i) ------------ (1-2i)(1+2i) all to the 2 i later (1 + 5 i - 6) ------------- (1 + 4 ) (5 i - 5) --------- 5 is (i-1) so do (i-1) to the power
*October 21, 2015*

**Math**

(1+i)^2 = 1 + 2 i - 1 = 2 i so (1+i)^4 = -4 2/-4 = -1/2
*October 21, 2015*

**PLEASE HELP**

You are welcome.
*October 21, 2015*

**PLEASE HELP**

when the other object is colder.
*October 21, 2015*

**physical science**

Everything has potential energy compared to something. It is relative with no true absolute zero. However if this point B is above some other point, the person has gravitational potential energy. If the person is moving, the person also has kinetic energy.
*October 21, 2015*

**Physics**

initial momentum = 3000*9 final momentum = (3000+m)*6 final momentum = initial momentum solve for m b) F = m a If a is less force is less. a is rate of change of velocity if velocity change is spread out over a longer time, a is less and F is less.
*October 21, 2015*

**e**

(x-3)13 = 91 13 x - 39 = 91 13 x = 130
*October 21, 2015*

**Physics**

F = m a F = -k x m a = - k x if simple harmonic motion x = A sin (2 pi t/T) v = A (2 pi/T) cos (2 pi t/T) a = -A(2 pi/T)^2 sin (2 pi t/T) = -(2 pi/T)^2 x so m (-2pi/T)^2 x= -k x (T/2 pi)^2 = m/k T = 2 pi sqrt(m/k)
*October 21, 2015*

**Physics**

frequency = constant * sqrt (k/m) 4 times m is 1/2 frequency or TWICE the period
*October 21, 2015*

**Physics**

distances from charges x1 = x-30 x2 = 78-x q1/x1^2 = q2/x2^2 1/x1^2 = 4.41 /x2^2 1/(x-30)^2 = 4.41/(78-x)^2 6084 - 156 x + x^2 = 4.41(x^2 -60 x + 900) solve the quadratic
*October 20, 2015*

**Art**

perspective, choose vanishing point in the distance.
*October 20, 2015*

**Physical Science**

You are welcome.
*October 20, 2015*

**Physical Science**

Huh? You SQUEEZED the gas P1V1 = P2 V2 V2 = (P1/P2) V1 1/2 not two
*October 20, 2015*

**MATH**

divide both side by 2.8 x = -9.24/2.8 which is -3.3
*October 20, 2015*

**correction**

5orry, 5 hours and 41 minutes
*October 20, 2015*

**PLEASE HELP**

500 km (1 hr/88 km) = 5.61 hr or one hour and 41 minutes
*October 20, 2015*

**math**

yes, correct
*October 20, 2015*

**MATH**

you sure do. Please make some attempt to do the problems. I will do only the first one. -5g - 6 for g= -2 -5(-2) - 6 10 - 6 4 10 -13
*October 20, 2015*

**physics**

F = m a assume same F from tires on road so as m decreases, a increases
*October 20, 2015*

**Analytical Mechanics**

define positive up Vi = + 1000 going up F = - m g - c v^2 = m dv/dt dv/dt = -g -(c/m) v^2 v = Vi - g t -(c/m)integral of v^2 dt z = Vi t - (1/2) g t^2 - (c/m) double integral of v^2 dt I do not think there is an analytical solution. You must resort to numerical integration.
*October 20, 2015*

**physcial science**

twice as many turns to double voltage
*October 20, 2015*

**physcial science**

half
*October 20, 2015*

**Calculus 1**

Sketch the graph like it said to do.
*October 20, 2015*

**world history**

found reason, listen to tape here. It is about her changing the official religion. http://www.biography.com/people/nefertiti-9421166
*October 19, 2015*

**PHYsics URGENT**

p = Patmosphere + rho g h = 1.013*10^5 + 1030*9.81*10900 for part b divide that by 1.013*10^5
*October 19, 2015*

**Chemistry**

H2 = 2 grams/mol O = 16 grams/mol H2O = 18 grams /mol so 14 grams H2 is 7 mol that means we get 7 mol of water 7 * 18 = 126 grams
*October 19, 2015*

**physics101 please**

everything is moving right so will continue to do so final momentum = initial momentum initial momentum =12,000*22 + 1200*16 final momentum = (12,000+1,200) v
*October 19, 2015*

**world history**

religion see http://www.biography.com/people/nefertiti-9421166
*October 19, 2015*

**physics101 please**

Ac = v^2/r = 26^2/120 F = m Ac = 1500 * 26^2/120 friction force between the road and the tires. Think about what happens if it is icy.
*October 19, 2015*

**Social Studies**

That is what the whole document is about but in brief; executive (president), legislative (congress) and judicial (court)
*October 19, 2015*

**Calculus i need help plz plz**

dy/dw = s^3/d^4 dy/ds = 3 w s^2/d^4 dy/dd = [d^4(0) - 4 w s^3 d^3 ] / d^8 = - 4 w s^3 / d^5 total change: dy = dy/dw * dw + dy/ds * ds + dy/dd * dd if all variables are 1 y = 1 then the changes dw = .02 ds = -.03 dd = .01 so dy = 1 * .02 - 3 *.03 - 4 * .01 = .02 -.09 - .04...
*October 18, 2015*

**Typo I bet**

maybe x^2 + 6 x - 1 ?
*October 17, 2015*

**Calculus**

A = x^2 A + dA = (x+dx)^2 = x^2 + 2 x dx + dx^2 if dx is small A + dA = x^2 + 2 x dx so dA = 2 x dx
*October 17, 2015*

**Chemistry**

http://www.endmemo.com/chem/compound/crs3.php This is Cr +6 not +3
*October 17, 2015*

**PreCalc**

The answer has to be positive as you know. 3 is already positive. sin x might be negative though so 3 |sin x| would be more appropriate than |3 sin x| although of course they are the same.
*October 16, 2015*

**Physics**

http://www.jiskha.com/display.cgi?id=1445015891
*October 16, 2015*