Monday

April 21, 2014

April 21, 2014

Total # Posts: 16,198

**do not understand question**

Is this the way the question is phrased in your book ?

**Chemistry**

first multiply by 10^-2 to get meters instead of centimeters so 3 * 10^8 m/s * 1 km/10^3m * 3600 s/hr = 10800 * 10^5 = 1.08 * 10^9 km/hr or type 3*10^8 m/s = km/hr Into a Google search box

**Math repost**

2 c + 3 L = 14.55 1 c + 2 L = 8.77 multiply second one by 2 2 c + 3 L = 14.55 2 c + 4 L = 17.54 -------------------- subtract -1 L = - 2.99 L = 2.99 then c = 8.77-2L = 2.79

**physics**

weight = 1.6 * 9.8 = 15.68 N T in each side of wire do right half, left the same 1/2 weight = 7.84 N half distance = 24.5 theta angle between vertical and wire Tan theta = 24.5/.149 theta = 89.65155 so cos theta = .00608152 T cos Theta = half the weight T = 7.84 N/.00608152 = ...

**Intermediate Algebra**

7 a + 2 f = 86 3 a + 4 f = 84 14 a + 4 f = 172 3 a + 4 f = 84 ------------------subtract 11 a = 88 a = 8 then 7(8) + 2 f = 86 so f = 15

**Physics.**

c 11/3 b 8/4 a 4/5 = 8/10 reverse the last two ? d 18/20 = 9/10

**Physics**

initial momentum North 800 * 18 East 800 * 18 final momentum North 1600 v sin T East 1600 v cos T (I am pretending I do not see that V = 18 sqrt 2 and T = 45 degrees) 800 * 18 = 1600 v sin T 800 * 18 = 1600 v cos T so sin T = cos T = 1/sqrt 2 That is T = 45 degrees so 800 * 18...

**physics**

weight - 126 g friction force = 126 * 9.81 * .7 = F if no acceleration

**physics**

loss of potential energy = m g h gain of kinetic energy = (1/2)m v^2 difference = work against friction which = F * 53 neters

**physics**

d = (1/2) a t^2 solve for a F = m a = mu m g so mu = a/g

**physics**

.24 g answered in another of your questions

**physics**

Hey, all of these are basically the same question. If you want to pass the course you better learn how to do one of them.

**phisecs**

bigger than, bigger than for example

**phisecs**

I answered this last night. Check at the bottom of this page.

**physics**

zero because F = m a = m*0.00

**Math**

copy and paste: this: (x^2+x-2) / (x^2-3x-4) here: http://www.mathsisfun.com/data/function-grapher.php

**Math**

y = (x-1)(x+2) / [ (x-4)(x+1)] when x = +1 , y = 0 when x = -2 , y = 0 when x = 0 , y = -2/-4 = 1/2 vertical when x = 4 or x = -1 = x^2/x^2 --> 1 when x is big positive or big negative

**Calculus**

(1/4)[-2x/(x^2-1) - ln(1-x)+ln(1+x) ] + c used Wolfram alpha

**Calculus**

at least it looks like the last one :)

**Calculus**

Whoops, yes, use Steve's

**Calculus**

probably sinusoidal y = a sin x + b cos x y' = a cos x - b sin x y" = -a sin x - b cos x = -y -a sx -b cx -a cx + b sx = 1 sx b = -a -a + b = 1 -2a = 1 a = -1/2 b = +1/2 so I get y = -(1/2) (sin x - cos x)

**Science**

600 V/0.1 m = 6000

**phisecs**

+8/3

**Algebra 1 (Reiny)**

3*10^2 * 1.5 * 10^6 = 4.5 * 10^8

**science**

The moon revolves around the earth. When it is between the earth and the sun, all we see is the side that is in shadow. That is "new moon" As it moves around so it is perpendicular to a line between earth and sun, we see the half that is lit. When it is behind the ea...

**Math**

(1/2) b h = 144 b = h/2 (1/2) h^2/2 = 144 h^2 = 144 * 4 so h = 12 * 2 = 24

**Algebra**

Good.

**Algebra**

as + af + ca = 778 af = as -195 ca = as -242 so as + as-195 + as-242 = 778 3 as = 1215 as = 405 you can take it from there I think.

**Math**

2^2 + h^2 = 16^2 4 + h^2 = 256 h^2 = 252 h = 15.87 ft By the way that ladder is dangerously steep.

**Calculus**

top and bottom both go to 0 try l'hopital derivative of top = 1(1)/(x+2)^2 --->1/4 derivative of bottom = 1 1/4 / 1 = 1/4

**chemistry**

1/3 of the original concentration

**math**

-8 + 3 - 8 + 1 - 8 + 3 - 8 + 1 - 8 52 44 47 39 40 32 36 28 29 21 maybe ?

**Algebra**

something like 6 use that distributive property 6. (2m - 4)(m^2 + 2m + 4) 2m (m^2 + 2m + 4) = 2 m^3 +4 m^2 + 8 m -4 (m^2 + 2m + 4) = 0 m^3 -4 m^2 - 8 m -16 -----------------------------------add 2 m^3 -16

**Algebra**

3. (r + 3)^2 My answer: r^2 + 6r + 9 YES

**Algebra**

2. (x - 2)(3x + 5) My answer: 3x^2 - 30x - 10 --------------------------- My answer, either FOIL or use distributive property FOIL 3 x^2 + 5 x - 6 x -10 = 3 x^2 - x - 10 distributive property x(3x+5) -2(3x+5) 3 x^2 + 5 x - 6 x - 10 remarkably similar

**Algebra**

1. (x^2 + 3x - 9) + (-4x^2 + 2x - 3) My answer: -4x^4 + 5x - 12 ------------------------------- my answer, add like terms x^2 - 4 x^2 = - 3 x^2 for example -3 x^2 + 5 x -12

**math**

LOL - do it Reiny's way !

**math**

divide ax^4+ 0 x^3 +bx^2 + 0 x +c by (x+1) a x^3 - a x^2 + (a+b)x - (a+b) remainder = a + b + c which must be zero

**Typo? advanced functions**

h(t)=-2t^3+3t^2+149 = 980 -2 t^3 + 3 t^2 - 831 = 0 There is no positive real root. I think a typo I bet you mean h(t)=-2t^3+3t^2+149t so -2 t^3 + 3 t^2 + 149 t - 980 = 0 nope, no real + roots I think a typo

**1 algebra question**

Hey wait a minute. I did your subtraction as you wrote it but maybe you meant difference between these two (6x^3 – 2x^2 +4) and (2x^3 + 4x^2 – 5) that is (+6x^3 – 2x^2 +4) (-2x^3 - 4x^2 + 5) ---------------------- add 4 x^3 - 6 x^2 + 9

**1 algebra question**

8x^3 + 2 x^2 - 1 I mean

**1 algebra question**

+a + b + c -d + e - f -------------subtract to subtract, reverse the sign of the lower line and add +a + b + c +d - e + f ---------------- then add a+d+b-e+c+f so (6x^3 – 2x^2 +4) -(2x^3 + 4x^2 – 5) ------------------subtract is the same as (6x^3 – 2x^2 +4) +(2x...

**Physics**

60 = (1/2)(3.37) t^2 solve fot t, the rolling time v = a t = 3.37 t that v is the speed at the cliff edge u = v cos 21 = horizontal speed until bottom Vi = -v sin 21 = initial speed up (negative of course) h = Hi + Vi t + (1/2) a t^2 now t is the time airborne 0 = 30 - v (sin ...

**Limits**

Huh? cos ( pi *16 /8 ) ?? cos 2 pi = 1 I do not see what this has to do with limits

**Algebra**

You are welcome :)

**Algebra**

LOL well from what you said all I can say is g(k) = -k^2 + 4 k + 1

**Froude number**

Great !

**Froude number**

if you multiply any lengths by 4, you must multiply the speeds by 2 to be at the same Fr.

**Froude number**

L is any old length on your model or ship or dam or whatever It just has to be the same length on the ship and the model and the speed measured at the bow or at the propeller tip as long as you are consistent from ship to model. The point is that you will get the same wave sha...

**Froude number**

I knew it was coming ! William Froude :) Fr = v/sqrt(Lg) v = n R or (1/2) n D (1/2) n D / sqrt (D g) = (1/2) n sqrt D/sqrt g = (1/2) n sqrt (D/g) the 1/2 does not matter, arbitrary constant

**physics**

F = m a G M m/R^2 = m v^2/R but T = 2 pi R/v time for circumference rounding so v^2 = (2 pi R/T)^2 = (2 pi)^2 R^2/T^2 so G M/R^2 = (2 pi)^2 R/T^2 G M/(2pi)^2 = R^3/T^2 ( but Kepler knew that :) = Rnew^3/Tnew^2 = (2R)^3/Tnew^2 = 8 R^3/Tnew^2 so Tnew^2 = 8 T^2 Tnew = 2 sqrt 2 T ...

**got to be a pie crust in there**

It is an ellipse on the bottom, pi has to be involved in the volume I think.

**calculus**

Let's just do the quarter of it over the right half 0 < x < 5 and multiply by 2 at the end that means the triangle has base 2y and height 6 everywhere so its Area is (1/2)(2y)(6) = 6y and a slice of volume is 6ydx we need to integrate that from x = 0 to x = 5 (and no...

**DRAGONWINGS NOVEL, PLS HELP**

and if they are not from connexus they are unlikely to be able to help.

**Math, anyone, plz help**

You are welcome, good luck !

**Math, anyone, plz help**

A tractor costs $15,450.00 and depreciates in value by 14% per year. How much will the tractor be worth after 3 years? 100 - 14 = 86 .86^3 = .636 .636 * 15450 = 9827.07

**Math, anyone, plz help**

A $6,000.00 principal earns 8% interest, compounded semiannually. After 35 years, what is the balance in the account? (1 point) 70 periods at 8/2 = 4% 1.04*70 = 15.57 times 6,000 = 93,429.71 compounding works, start young :)

**Math, anyone, plz help**

A $3,300.00 principle earns 4% interest, compounded annually. After 3 years, what is the balance in the account? (1 point) ( I think it’s $3,712.05) 1.04^3 = 1.12486 3,300 * 1.12486 = 3712.05 correct

**Math, anyone, plz help**

y=-3x^5 represent an exponential function? (1 point) No y = -3* 5^x would be. It is the exponent which must be the variable

**Math, anyone, plz help**

Try them first please. I already know how.

**Math, anyone, plz help**

the second part is time = distance / speed which I am sure you know. By the way radio signals and light are both electromagnetic signals and both travel at the speed of light which we all remember and we really do remember forever is about 3*10^8 meters/ second in a vacuum.

**Math, anyone, plz help**

The first one is really really easy and you did not try it. 5.88 * 10^12 * 1.23 * 10^2 = ?

**Math**

Well, 6 is a little different: * 6. The sum of $305 was divided among three people so that the second received $4 less than twice as much as the first, and the third received $23 more than the second. How much did each person receive? first = x second = 2x-4 third = 2x-4+23 = ...

**Math**

1. Find two numbers whose sum is 84 and one number is 18 more than the other. Answer: 84-18=2x x=33 84+18=2x x=51 ***************** Oh my, you have me confused. Either you wrote it wrong or you answered it wrong. x + (x+18) = 84 2 x + 18 = 84 2 x = 66 x = 33 x+18 = 51 ********...

**math**

161 / 34 = 4.74 so he will need five boxes since I assume he is not allowed to take part of a box

**Sloshing water frequency**

sorry, have shallow water limit wrong speed proportional to square root of depth v = k L^.5 T = L/v = L/(k L^.5) = c sqrt L so frequency = constant / sqrt L so same ratio, 1/sqrt 10

**Sloshing water frequency**

by the way if the wavelength is long compared to the water depth then the speed is proportional to the depth. v = k L T = L/v = L/kL = 1/k and the speed would be so much faster in the deeper pool that the period would be the same.

**Sloshing water frequency**

http://www.jiskha.com/display.cgi?id=1392897814 Sorry, I was rowing this morning and did not see this question. Finally a question I am used to :) Naval Architect, Gloucester, MA

**Hydrodynamics**

time to cross pool = L/v = T where T is proportional to period or 1/f so L = k v /f where k is some constant f = k v/L now I do not know what you have studied. I hope you know that if wavelength is short compared to depth the speed of the wave is proportional to the square roo...

**Physics**

Inward force needed =m a = m v^2/R = 600 (900)/120 = 4500 Newtons inward down slope component = 4500 cos 25 Force up slope = Ff friction weight down slope = m g sin 25 = 2488 Net force down slope = 2488 - Ff so 2488-Ff = 4500 cos 25 Ff = 2488 - 4078 Ff = -1590 N so 1590 DOWN t...

**physics 2**

Power = i^2 R energy = power * time = i^2 R t in Joules t = 60 seconds set that equal to heat energy used to warm the battery type this into Google search box 0.2 kcal/kg K = Joules/kg K to get C = 836.8 J/kg K i^2 R t = 836.8 * 20kg * (delta T) solve for delta T

**Physics**

train goes 27 t meters car goes 27 t + 29 meters so 27 t + 29 = 38 t + (1/2)(2) t^2

**Physics**

mass of system = M = .082 + 863 Kinetic energy at bottom = potential energy at top (1/2) M v^2 = M g (.045) or v^2 = 2 (9.8)(.045) solve for v, total velocity at bottom after collision note - the masses do not matter

**Physics**

diameter does not matter p = density * g * depth (the weight of water in a 1 m^2 column) so water weighs 1000 kg/m*3 so we are talking a mass of 1000 * 20 20,000 * 9.81 = 196,200 or 1.96*10^5 Newtons/m^2 or Pascals HOWEVER on to of that you have the air pressure which is about...

**Physics**

F = m a Would it not be easier to do the problem than to type it here?

**Physics**

normal component of weight = 45*9.81* cos 41 so friction force = 0.45* 45*9.81*cos 41 component of weight down slope = 45*9.81 * sin 41 so 45 a = 45*9.81*sin 41 - .45*45*9.81*cos 41 or a = 9.81* (sin 41 - .45 cos 41)

**Math help**

-3 = x + 1

**Black Death**

It will not help you much but I have a recently written book called "The Sea and Civilization". It spends quite a lot of time tracking the plaque through China and the rest of mainland East Asia and then to the Black Sea where it was picked up by a trading vessel fro...

**Honors Physical Science**

(1/2) m v^2 you know is 12500 when v^2 = 625 so calculate m weight = m g = 3.8 (m) Newtons

**Math**

(29/8) h = 29 h = 8

**phisecs**

v = a t = 20.15 m/s

**PHYSICS**

v = her speed c = current speed (v+c) * 2 = 10 (v-c) * 3 = 10 v + c = 5 = 15/3 v - c = 10/3 --------------subtract 2 c = 5/3 c = 5/6

**Math**

fine

**Math**

In the second one you mean c.) 30 pages per hour

**Math**

octa for eight faces dodeca is two + ten = 12 faces ( not a bad approximation to a sphere, count on soccer ball, I forget)

**Math-- Check My Answers Please**

You are welcome :)

**Math-- Check My Answers Please**

second also wrong along y it is difference in y 103 - 2 = 101 which is d.)

**Math-- Check My Answers Please**

Bonnie has a rectangular photographic print that is 5 inches wide and 7 inches long. If she multiplies both the length and width by 1.5, how will the perimeter of the print increase? a.) It will be 1.5 times the original size. b.) It will be 1.75 times the original size. *****...

**Math**

9/24 is not 3/4 others ok 6/16 is not 2/5 (6/15 is though)

**PHYSICS**

average speed during constant acceleration = (end speed+start speed)/2 = (0 + 28.8)/2 = -14.4 m/s Now if you want the average force for the next part of the qustion F = d momentum/ d time = - mass of driver (28.8) /(.93/-14.4)

**PHYSICS**

rowing speed = v speed upstream = (v-c) speed downstream = (v+c) (v+c) * 2 = 10 (v-c) * 4 = 10 or (v-c) * 2 = 5 2 v + 2 c = 10 2 v - 2 c = 5 ------------------add 4 v = 15 v = 15/4 = 3.75 km/hr

**Finite Math and Applied Calculus**

first 35 years 35 * 12 = 420 months = n r = .036/12 = .003 monthly interest rate p= present value of sinking fund N = deposit each period of 1 month = 500 p = N [ (1+r)^n - 1 ] /r p = 500 [ (1.003)^420 - 1 ] / .003 p = 419,796.33 after 35 years now the final 10 years quarterly...

**Math ~ Check Answers ~**

You are welcome :)

**Math ~ Check Answers ~**

Now Wendy, look at your second problem Kevin plotted a linear equation on a graph with 18 as the y-intercept. Which of following could be the equation plotted by Kevin? a.) 1/2y = 9x + 5 b.) 3x = 6 -1/3y < ---------- YES c.) 4x + 18y = 21******** NO d.) 7x + 2y = 38

**Math ~ Check Answers ~**

(1/3) y = -3 x + 6 multiply both sides by 3 y = -9 x + 18

**Math**

9/24 is not 3/4 others ok 6/16 is not 2/5 (6/15 is though)

**Math**

6/8 , 12/16 , 36/48 ...... 2/5, 14/35, 6146/15365 5/10 = 1/2 4/8 = 1/2 the same

**PHYSICS**

Larger diameter? More massive?

**PLS HELP ME WITH ONE MATH QUESTION!!???**

Or I suppose one could make one out of play dough :)

**MATH**

Nothing

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