Thursday

May 5, 2016
Total # Posts: 26,169

**Physics**

volume of water displaced = .1034^3 = .0011055 m^3 times density of water which is about 1000 kg/m^3 =1.106 kg of water displaced Archimedes says we can float that much mass .150 + m = 1.106 m = .956 kg = 956 grams
*May 5, 2016*

**Physics**

Why would surface area have anything to do with it?
*May 5, 2016*

**Physics**

diameter has nothing to do with it. rho g h = 1000 kg/m^3 * 9.81 * 30.34 Pascals
*May 5, 2016*

**trig, precalc, math, algebra, trigonometry**

cos theta = adjacent/hypotenuse call adjacent side v call hypotenuse 1 then cos theta = v opposite side = sqrt(1^2 - v^2) tan theta = sqrt(1-v^2) /v
*May 5, 2016*

**Physics**

If x is horizontal, there is no x component of weight. If x is down the slope then assuming you really mean 76 kg it is 76 * 9.81 * sin 10
*May 5, 2016*

**Algebra**

n and 2n-1 n + 2n - 1 = 20 3 n = 21
*May 5, 2016*

**Science**

I agree
*May 4, 2016*

**PHYSICS**

You push them to make them faster increasing their momentum. However they can not go a lot faster so that increased momentum shows up as mass rather than velocity. m = mo/sqrt (1 -v^2/c^2) as v ---> c the mass gets huge approaching undefined.
*May 4, 2016*

**Math**

x and x+5 x(x+5) = 6 x^2 + 5 x - 6 = 0 (x-1)(x+6) = 0 x = 1 or -6 if x = 1 x+5 = 6 and if x = -6 x+5 = -1
*May 4, 2016*

**Parametric Curve**

LOL e is a horizontal line, y = 5 b is a parabola, do what I suggested.
*May 4, 2016*

**Parametric Curve**

Well, I suppose if you do not see it as is, you can do x and y for example in (a) y = 4t-2 x = t+1 so t = x-1 y=4(x-2) - 2 y = 4 x -10 dx/dt=dy/dt = 0 so constant speed (d) If you do no see it is a circle, do the same thing again y = (2t+1) cos t y^2 = (2t+1)^2 cos^2 t x^2 = (...
*May 4, 2016*

**math nid this asap tyy**

m g h = (1/2) m v^2 h = v^2/2g v the same v^2 = 2 g h 2 * 9 .8 * 2.35 = 2 * 1.6 * h h = 14.4 meters
*May 4, 2016*

**PLEASE HELP WITH ALGEBRA**

You have 185 bands in the box pink 95/185 = 19/37 brown 90/185 = 18/37
*May 3, 2016*

**0 through 10 is 11 spaces**

10 equal sections from 0 to 10 ??? No, that is 11 1 to 10 would be ten sections 3 or 6 or 9 means answer = 3/11
*May 3, 2016*

**Math**

LOL, I will never say.
*May 3, 2016*

**Math**

21^2 = 441 22^2 = 484 23^2 = 529
*May 3, 2016*

**Physics**

well, I get 1.47*10^2 Joules Yes, work done = change in kintic energy
*May 3, 2016*

**Physics**

work = force * distance in direction of force 150 J = 10 d d = 15.0 m
*May 3, 2016*

**Maths yr 6**

(4/5) hr/manhouse * 3 man = 12/5 hr/house = 2 2/5 hr = 2.4 hr
*May 3, 2016*

**statistics**

50 shipped first one ok 29/50 second one 28/49 third one 27/48 etc down to eight of them then multiply
*May 3, 2016*

**history**

In question 5 I do not think the act was about age requirements but it was about racial discrimination. It allowed people of all races to register to vote and vote, and that includes primary elections.
*May 2, 2016*

**check for typos**

length or height? How many feet is A ?
*May 1, 2016*

**Math**

I already went through trying to draw a 60, 60, 60, 90 triangle with this student.
*May 1, 2016*

**Math**

You are welcome :)
*May 1, 2016*

**Math**

whew, finally someone got one right !!! :)
*May 1, 2016*

**MATH**

NO, To make D you need three 60 degree angles and a 90 degree angle. Try to draw that.
*May 1, 2016*

**MATH**

An equilateral triangle has three 60 degree angles. That leaves no corner for a 90 degree angle.
*May 1, 2016*

**baloney**

Please check for typos !! If you used length, width and thickness you probably mean ft^3 not ft^2. That messed you up big time when you wrote 144 which is square inches per square foot. What you want is CUBIC feet per CUBIC yard which is 3^3 = 27 ft^3/yd^3 ( despite the fact ...
*May 1, 2016*

**mathematics-change of subject of the formula**

(A/pi)^2 = r^2 (h^2-r^2) =-r^4+h^2r^2 r^4 - h^2 r^2 + (A/pi)^2 = 0 r^2 = [h^2 +/-sqrt(h^4-4A^2/pi^2)]/2 r = sqrt { [h^2 +/-sqrt(h^4-4A^2/pi^2)]/2 }
*May 1, 2016*

**Math**

(x-11)^2 = r^2 = x^2 - 22 x + 121 so I do not get d
*May 1, 2016*

**math**

.75 miles/4.5 min *60 min/hr = 10 mi/h
*May 1, 2016*

**typo**

If it grows exponentially you mean 15,000 * 1.07^x in other words compounding not 1.07 x In that case C is correct 1.07^12 = 2.25 A rough estimate to remember is that 7 percent compounded for ten years is about a doubling.
*May 1, 2016*

**CONVERSIONS**

there are 9 ft^2/ yd^2 because 3*3 is 9
*May 1, 2016*

**MEASUREMENTS**

0.254296875 mi^2 if it is really 162.75 acres If however that is a typo and you mean 1642.75 acres then 2.566796875 mi^2
*May 1, 2016*

**Math - typo ?**

4y = 3 x y = .75 x + 0 slope = +.75 line is not in quadrant 2 but in one or three
*May 1, 2016*

**math**

You could just as easily lose 5 or more as win five or more. The triangle is symmetric about that middle point note C = 252 for point C10,5 then 210 to the left and 210 to the right. The middle point can go either way Too bad you had an even number of questions :) That is what...
*May 1, 2016*

**Ms Sue, not symmetric. Could get 5 wrong !**

Note my check comment
*May 1, 2016*

**math**

note that if I split the probability of getting 5 right in half I would get .123 less which would be .5 :) (good check)
*May 1, 2016*

**math**

binomial distrution p(5) = C(10,5).5^5 .5^(10-5) = 252*.5^10 = .246 p(6 ) = C(10,6).5^6 .5^4 = 210 * .5^10 = .205 p(7) = 120 * .5^10 = .117 p(8) = 45 * .5^10 = .044 p(9) = 10 * .5^10 = .01 p(10) = 1 * .5^10 = .001 now add .623
*May 1, 2016*

**math trick question**

The same as the supplement of a supplement :)
*May 1, 2016*

**math**

a/b = b/(a-b) b^2 = a^2 - ab a^2 - ab -b^2 = 0 a = [b +/- sqrt(b^2 +4 b^2) ]/2 a = b [ 1 + sqrt 5 ]/2 a = 1.618 b sure enough now 3.7 could be a or b if b = 3.7 then a = 5.99 about 6 if a= 3.7 then b = 2.29 about 2.3
*May 1, 2016*

**math-middle school**

well, I suppose in some world B could be a negative angle, but not in ours.
*May 1, 2016*

**7 th grade math**

14/20 = 7/10 = 0.70 0.70 * 300 = 210 0.70 * 100 = 70 0.70 * 240 = 168
*May 1, 2016*

**Calculus**

k = P V^1.4 k = 40 * 14^1.4 k = 1609 so P = 1609 V^-1.4 dP/dt = 1609 (-1.4)(V^-2.4) dV/dt = -2253 (14)^-2.4 * -1 = 4 psi/s
*May 1, 2016*

**Math**

speed = 70+80 = 150 distance = 300 time = 300/150 = 2 h
*May 1, 2016*

**physics**

3000 * v = 15 * 1.5
*May 1, 2016*

**Math NEED HELP!!!!!!**

http://www.mathsisfun.com/geometry/construct-linebisect.html
*May 1, 2016*

**Math**

4*8 = 32 1*2 = 2 32/2 = 16
*May 1, 2016*

**physics**

185 * 8 = 1480 Joules 1480 Joules = 3537 cal
*April 30, 2016*

**Chemistry**

How many molecules do you have? Well how much mass in a mol? 3*12 + 7*1 + 16 + 1 = 60 grams for 6.022*10^23 molecules so we have 6.022*10^23 * 85.9/60 = 8.62*10^23 molecules each of those molecules has 3 carbon atoms 3*8.62*10^23 = 25.9 *10^23 =2.59 * 10^24 carbon atoms
*April 30, 2016*

**physics**

Fx = -a x^4 I assume you mean F= -25 x^4 dW = F dx = -25 x^4 dx W = -(25/5)x^5 at x = 1.25-at.75 W = -5 (1.25^5 - .75^5)
*April 30, 2016*

**Maths**

try reading here: http://www.mathsisfun.com/algebra/factoring.html
*April 30, 2016*

**math**

Yes, to do it on the number line start at 0 go left 8 to - 8 go right 14 to +6
*April 30, 2016*

**check list of answers below**

This has been asked over and over and over again, look below.
*April 30, 2016*

**typo**

You mean V = (4/3) pi r^3 dV/dt = (4 pi r^2) dr/dt (You really do not need calculus. It is the surface area times dr/dt)
*April 30, 2016*

**MATH**

No, because 3+5 = +8 , not 15
*April 30, 2016*

**math**

-9 + 5 + x = -1 -4 + x = -1 x = +3
*April 30, 2016*

**MATH**

-4 - 2 = -6
*April 30, 2016*

**Geography -Yr10**

During the second half of the 19th century, river shipping was of great importance, but, with growing competition from railways and demand for irrigation water (first used at Mildura in 1886), navigation practically ceased. ================================ In other words they ...
*April 30, 2016*

**Math**

weight at top = 15 -.1*50 = 10 average weight = (15+10)/2 = 12.5 12.5 * 50 = 625 ft pounds
*April 30, 2016*

**Math**

You are welcome.
*April 30, 2016*

**Math**

No, same answers both ways.
*April 30, 2016*

**Math**

I used the kinematics because I did not know if you knew how to integrate velocity to get distance.
*April 30, 2016*

**Math**

oh well v(t)= 38-2t or dx/dt = 38 - 2 t then x = c + 38 t - (1/2)(2)t^2 c = x when t = 0 call it 0 here x = 38 t - t^2
*April 30, 2016*

**Math**

I do not know if you know calculus or if you have kinetatic equations in your text. What we have here is a constant acceleration of -2 ft/s^2 a. 0 = 38 - 2 t 2 t = 38 t = 19 s b. d = Vi t + (1/2) a t^2 = 38 (19) - 19^2 = 19(19) = 361 feet or use average speed for 19 seconds...
*April 30, 2016*

**Math**

yes, circumference = pi D = 8.4 pi
*April 30, 2016*

**Geometry**

yes, If you use google search type in 45 yards = cm and see what happens
*April 30, 2016*

**math**

.6 * 255.5 = 153.3 leaked out .3 oz/s * t = 153.3 oz t = 153.3 /0.3 = 511 seconds
*April 30, 2016*

**Rt**

31+n = 2(7+n) 31 + n = 14 + 2 n 17 = n so in 17 years then check 7 + 17 = 24 31 + 17 = 48 sure enough twice 24
*April 30, 2016*

**Geography - Yr10**

Note particularly : " .....From the 1970s the emphasis changed to community facilities such as libraries and parks, maintenance of local roads, town planning and development approvals, and local services such as waste disposal. Child care, tourism and urban renewal were ...
*April 29, 2016*

**Geography - Yr10**

I see from your other question about Murray River that you are probably in Australia. I know little about Australia, being from Massachusetts in the USA but perhaps look here: http://en.wikipedia.org/wiki/Local_government_in_Australia
*April 29, 2016*

**Math (please help)**

(1/4)in * 6 ft/in = 1.5 ft/side so 2.25 ft^2 /square Bathroom = 2.25*6=13.5 ft^2 Bedroom = 2.25*20= 45 ft^2 Living room = 2.25*28=63 ft^2 tiny house a. 5 * 13.5 b. (18/9)(45+63) c. tile is $5/ft^2, carpet is $2/ft^2
*April 29, 2016*

**science**

Did it start at zero speed? If so 300 = (1/2) a t^2 = .5 a *225 a = 600/225
*April 29, 2016*

**math**

(4/3)x - 4 - (6/5)x + 9 (20/15)x - (18/15) x + 5 (2/15) x + 5
*April 29, 2016*

**physics**

The speed is constant. All you need is the vertical component. (30/4) cos 45
*April 29, 2016*

**math**

new length = 15+x new width = 12+x so the last one
*April 29, 2016*

**Pre Calculus**

L = 13 - 2x w = 11 - 2x V = (13-2x)(11-2x)x V = (143 - 48 x + 4 x^2)x V = 4 x^3 -48 x^2+143 x find where dV/dx = 0 0 = 12 x^2 - 96 x + 143 x = [ 96 +/- sqrt(9216-6864)]/24 x = [96 +/- 48.5 ]/24 x = 1.98 in or x = 6.02 (too big, no width left) so about 2 inches high
*April 29, 2016*

**physics**

.388 kg ice melt it and warm it to 45 C .388 [ 333,000 + 45(4186) ] = 202,292 Joules into what was ice = m [2256,000 + 55(4186) ] = 2,486,230 m m = 202,292/2,486,230 = .0814 kg = 81.4 grams
*April 29, 2016*

**Maths**

each pipe does one tank/12 hr call that 1 tank/12 hr pipe 1 tank/12hrpipe * 4 pipe * 2 hr = (8/12) tank = 2/3 of a tank
*April 29, 2016*

**Math**

835 cm / 15 cm = 55 2/3 55 pieces + 2/3 * 15 = 10 cm left over
*April 29, 2016*

**maths**

100 - 30 = 70 .7 * 60 = 42
*April 29, 2016*

**Physics**

I assume you made a typo and mean 1.6 * 10^15 Liters 1 liter water = 1 kg a pint is a pound the world around :) m g h = 1.6*10^15 kg * 9.81 m/s^2 * 143 m = 2245 * 10^15 = 2.245 * 10^18 Joules
*April 29, 2016*

**Math**

probability that she sees a bird on any old day = 18/30 = 0.6
*April 28, 2016*

**huh?**

180 was the answer, .3 * days 420 is days you do NOT hear thunder.
*April 28, 2016*

**college mathematics**

yes --- angle side angle
*April 28, 2016*

**college mathematics**

yes --- side side side
*April 28, 2016*

**homework**

assume you mean x^(8/9) pi y^2 dy from y = 0 to y = 1 pi x^(16/9) dy but dy = (8/9) x^-(1/9) dx so (8/9)pi x^(15/9)dx from 0 to 1 (8pi/9) (9/24)x^(24/9) (8 pi/24) = pi/3
*April 28, 2016*

**Physics**

I guess you mean north of east and east of north east = 1000 cos 40 + 500 sin 20 north = 1000 sin 40 + 500 cos 20 east = 937 north = 1113 distance = sqrt(937^2+1113^2) tan angle north of east = 1113/937
*April 27, 2016*

**Math**

width = 1.5 1.5 * 3 * 6 = 18+9 = 27 ft^3 which is one cubic yard
*April 26, 2016*

**Science**

calibrate it. Mark points on it that are he same temp as the real thermometer shows, say in cold water and hot.
*April 26, 2016*

**Math**

7 * 2.5 * h = 175 h = 10
*April 26, 2016*

**math**

Can not, sorry, rules.
*April 26, 2016*

**math**

Note above that she answered a question at 6:41 EDT
*April 26, 2016*

**math**

Your guess is as good as mine.
*April 26, 2016*

**math**

1, 89 , 67 , 89 , 7, 5 , 45 , 7
*April 26, 2016*

**math**

What do you mean? They all are except 0.
*April 26, 2016*

**math**

I suppose
*April 26, 2016*

**math**

Hi neighbor
*April 26, 2016*

**math**

1*1*5/(2*2*6) = 5/24
*April 26, 2016*

**Math**

I said 280 + 4 w = 420 so 4 w = 140 w = 35 mph wind speed now go back and get v
*April 26, 2016*