Saturday

April 30, 2016
Total # Posts: 26,118

**Calculus**

inverse would be time for a specific population 1+749 e^-.15t = 7500/p 749 e^-0.15 t = (7500-p)/p e^-.015 t = (7500-p)/(749 p) e^.015t = 749 p/(7500-p) .015 t = ln [ 749 p] - ln [7500-p)] t = 66.7 [ln 749 p - ln(7500-p)] we had 10 when t was 0 so check t = 66.7[ ln 7490 - ln ...
*January 28, 2016*

**Pre-calculas**

Is the point at the bottom or the top? whichever way you draw it Volume of a cone = (1/3)pi R^2 x where r is the radius of the surface and x is distance from the tip r/x = 9.5/ 16 = .594 so r = .594 x v = (1/3) pi (.594x)^2 x v = .369 x^3 dv/dx = 1.11 x^2 dv/dt = 1.11 x^2 dx/...
*January 27, 2016*

**Math**

yes, only one that has angles less than 90 and adds to 180
*January 27, 2016*

**physics**

Vi = initial speed up u = constant horizontal speed find t, time in air Vi = 135 sin 18.3 = 39.25 u = 135 cos 18.3 = 128.2 d = u T find T the time in air v = Vi - 9.8 t at top where v = 0 and t=T/2 0 = 39.25 - 9.8 t t = 4.005 s so T = 2 t = 8.01 seconds in the air d = u t = ...
*January 27, 2016*

**Math**

1700 * 100 / 8500 = 20 %
*January 27, 2016*

**Algebra**

n n+2 n+4 n+6 ---- 4 n + 12 = 80 4 n = 68 n = 17 17, 19 ,21 ,23
*January 27, 2016*

**Math**

make a sketch !!! a diagonal would for example be from B to D change in x = 1 - -1 = 2 change in y = -3 - +3 = -6 sqrt (2^2+6^2) = sqrt 40 = 2 sqrt 10
*January 27, 2016*

**Algebra**

n + n+2 = 1306 2 n = 1304 n = 652 n+2 = 654
*January 27, 2016*

**Math**

Agree, only one with all less than 90 and adds to 180
*January 27, 2016*

**Math**

Remember 40% LOSS is 60% LEFT :)
*January 27, 2016*

**Math**

.6 * 300 = 180 left after 40% trim .4 * 180 = 72 left to eat
*January 27, 2016*

**math**

You are welcome.
*January 27, 2016*

**math**

1.03^10 = 1.344 times 19900 = 26744 You got it
*January 27, 2016*

**Algebra**

n + n+1 + n+2 3 n + 3 = 930 3 n = 927 n = 309 and 310 and 311
*January 27, 2016*

**English**

because gh is two consonants http://www.howtospell.co.uk/doubling-up-rule
*January 27, 2016*

**Physical Science**

Yes, assuming electromagnetic (not water or sound or whatever)
*January 27, 2016*

**Math**

(200/5000)100 = 20000/5000 = 20/5 = 4%
*January 27, 2016*

**Algebra**

n + n + 1 = 529 2 n = 528 n = 264 n+1 = 265 add them to check
*January 27, 2016*

**math**

total rise = 112 - 149 = -37
*January 27, 2016*

**math**

you have 12 girls put one girl and 3 boys in each of 12 groups
*January 27, 2016*

**Math**

4n+2 = 14 ? 4 n = 12 n=3 2n = 6 2n+2 = 8
*January 27, 2016*

**physics**

Rx = 15 cos 250 = -5.13 m Ry = 15 sin 250 = -14.1 m ============================ new one is - 2 times old 250 - 180 = 70 degrees is opposite Rx = 30 cos 70 = 10.3 Ry = 30 sin 70 = 28.2 R^2 = (Rx^2+Ry)^2 = 30^2 (sin^2+cos^2) = 30^2 so it is 30 of course direction is the old ...
*January 27, 2016*

**physics**

I rounded .115 to .12 in part a (as instructed :) If they use 4.9 (1.15)^2 they would get 6.48 which rounds to 6.5
*January 27, 2016*

**physics**

t = distance/speed = .115 * 10^-6 seconds which is 1.2 *10^-7 seconds h = (1/2) g t^2 h = 4.9 (1.44)(10^-14) h = 7.1 * 10^-14 meters
*January 27, 2016*

**Physics**

F = k Q1Q2/r^2 here r = .115 so let (k/r^2) = c constant Fnorth = -(3.17*3.96*10^-12)c Feast = +(3.17*5.03*10^-12)c magnitude = sqrt (Fx^2 + Fy ^2)
*January 27, 2016*

**Physical Science**

solids are harder to squish. look here: https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/sound-topic/v/relative-speed-of-sound-in-solids-liquids-and-gases
*January 27, 2016*

**physics**

C runs 4.09 t meters C runs 4.28 t meters 4.28 t - 4.09 t = 94
*January 27, 2016*

**les/math**

original box x (2x)(5x) = 80 x^3 = 8 so x = 2 2x = 4 5x = 10 now new box 4 * 6 * 12 = 288 cm^3 increase = 288 - 80 = 208
*January 27, 2016*

**physics**

1490 + 25,000 tan 2.6 = h h = 1490 + 1135 h = 2625 meters
*January 27, 2016*

**Math**

Yes, could have any old value, including the same.
*January 27, 2016*

**math**

h * 6 = 102 h = 102/6 = 17 17 what though? inches,feet meters? decimeters? elbows? miles? kilometers? Is Rita a doll or a dinosaur?
*January 27, 2016*

**Physics**

- (1.2*10^4 )(1.6*10^-19) = 1.9 *10^-15 C = 1.9 * 10^-9 µC
*January 27, 2016*

**math**

a taxi ride costs 5 dollars to start the meter and then 4 dollars per mile. I have 37 dollars. How far can I ride? ( I guess I will not leave a tip :( 4 x = 37 - 5 4 x = 32 x = 8 miles
*January 27, 2016*

**Math**

ln(2x+3)^4 = 11 e^ln(2x+3)^4 = (2x+3)^4 = e^11 (2x+3) = (e^11)^.25 = e^2.75 = 15.64 2x = 12.64 x = 6.32
*January 27, 2016*

**Math**

Hey Rita, read what you wrote. We have no idea what your scale ratio is hint ratio of areas = ratio of lengths^2 2/1 in length is 4/1 in area (and 8/1 in volume)
*January 27, 2016*

**history .**

I agree with A for both. However I am not a history teacher.
*January 27, 2016*

**Math**

Log2(x)+log2(x-3)=2 2^[Log2(x)+log2(x-3)] =2^2 2^log2(x^2-3x) = 2^2 (x^2-3x) = 4 x^2 - 3 x - 4 = 0 (x-4)(x+1) = 0 x = 4 or x = -1
*January 27, 2016*

**Math**

2log6(4x)=0 log6 (16 x^2) = 0 6^log6 (16 x^2) = 16x^2 = 6^0 = 1 so x^2 = 1/16 x = 1/4 normally I would say also -1/4 but try to take the log of -1 :)
*January 27, 2016*

**Physical Science**

No, I disagree. It has to transfer heat to something colder, like a vat of liquid air or the surface of Lake Superior in February.
*January 27, 2016*

**Functions 11**

well b^2-4ac = 81-24k if that is positive, two real roots if it is zero, you have one root twice (the parabola just bounces off the x axis at x = -b/2a) if it is negative there are no REAL roots (although there are two complex conjugate solutions)
*January 27, 2016*

**Chemistry 101**

.785 v = 2 v = (2/.785) cm^3
*January 27, 2016*

**Physics**

Newtons force = F = .1 kg * 9.81 x = 0.10 meter k = F/x = 9.81 N/m
*January 27, 2016*

**Math**

use -4y for x in the second equation -4 y + 5 y = 2 so y = 2 then x = -4(2) = -8 (-8 , 2)
*January 27, 2016*

**Physics**

I took this in 1955 and do not need practice. If you get stuck I will help but I will not do all the problems for you. By the way in Naval Architecture we have a term called "tons per inch" for small changes in draft. It proportional to rho g * area of water line ...
*January 27, 2016*

**Physics**

(1000 kg/m^3 * volume) - 1.8 kg
*January 27, 2016*

**Physics**

You mean 1.8 * 9.81 N
*January 27, 2016*

**PHYSICS**

weight component down slope = m g sin A = force component up slope = F 50 (1/2) = 25 N = F
*January 27, 2016*

**Physics**

The kinetic energy alone is (1/2) m v^2 = 212 * 10^12 so there is a typo somewhere either in the problem statement or in the answer.
*January 27, 2016*

**Math**

Matt had x May had 3x 4 x - 50 = 70 4 x = 120 x = 30 ======================= check Matt 30 May 3*30 = 90 sum = 120 120 = 50+70
*January 27, 2016*

**math**

tan 30 = h/a tan T = h/2a tan T = (1/2) tan 30 T = 8.21 degrees
*January 27, 2016*

**W Hist**

semiconductors sitting around staring at screens no horse messes stinking up the city streets
*January 26, 2016*

**Math**

6 * 3 * 2 = 6 * 6 = 36 ft^3
*January 26, 2016*

**math**

2*2*2*2*2*2
*January 26, 2016*

**Physics**

vertical problem: Vi = 68 sin 25 = 28.7 m/s h = Vi t -4.9 t^2 h = 28.7 t - 4.9 t^2 horizontal problem: u = 68 cos 25 = 61.6 m/s t = 50/61.6 = .811 s so h = 28.7(.811) - 4.9(.811^2)
*January 26, 2016*

**Pre Algebra**

-1 11/16 + 4 1/6 = - 27/16 + 25/6 sure enough = -81/48 + 200/48 agree = 119/48 = 2 23/48 yes ============================ NO! -1 33/48 + 4 8/48 = 3 -25/48 = 2 + 48/48 -25/48 = 2 + 23/48
*January 26, 2016*

**?**

Please proof read initially at rest maybe? 12 what? /s^2 meters, feet ? 205 what? seconds, meters ? feet? miles? after 205 what again? 12 m/s^2 for how long ? Is this after the first question using that final for this initial velocity?
*January 26, 2016*

**math**

Yours is much better. I got off on that both queens tack :)
*January 26, 2016*

**math**

Go with jolly rancher !
*January 26, 2016*

**whoops**

what I gave you was for a specific rank, like two queens multiply by 13 because there are 13 ranks
*January 26, 2016*

**math**

4/52 * 3/51
*January 26, 2016*

**Science**

storage space, closet ?
*January 26, 2016*

**typo?**

You need to specify a time before the encounter
*January 26, 2016*

**History**

Well, I suppose D, but I do not think communes were that large as a rule.
*January 26, 2016*

**math**

No, you can not copy and paste to this site.
*January 26, 2016*

**Math**

3 times as many cookies takes 3 times as many cups of sugar so 6 cups 2 cups/ 2 dozen = 6 cups/6 dozen
*January 26, 2016*

**physics**

m v^2/r 2500 (25)/50 = 1250 Newtons
*January 26, 2016*

**Physics**

dw/dt = -10 - 4.42 t so w = -10 t - 2.21 t^2 + constant find constant at t = 0 71.6 = -10(0) - 2.21(0)^2 + c so c = 71.6 w = 71.6 - 10 t - 2.21 t^2 put in t = 2.73 Now the angle dTheta/dt = w = 71.6-10 t -2.21 t^2 so Theta = 71.6 t - 5 t^2 - (2.21/3)t^3
*January 26, 2016*

**Physical sciences**

Fx = 30 cos 60 - 40 cos 60 Fy = 30 sin 60 + 40 sin 60 F = sqrt (Fx^2 + Fy^2) Tan theta = Fy/Fx Note - Theta is in quadrant 2 because 40>30 Use 180 - the magnitude of the angle
*January 26, 2016*

**Physics**

from the plus plate toward the negative plate Remember that if you integrate along them you get the voltage difference.
*January 26, 2016*

**Physics**

You do not say what the moment of inertia of the Merry Go Round is. I will call it I 39.4 revs/min (2 pi rad/rev)(1 min/60s) = 4.13 radians /s = W1 omega of John = v/r = 6.36/3.21 = 1.98 rad/s Initial angular momentum = I (4.13) + 48.4(3.21)^2 (1.98) Final I = I + 48.4(3.21)^2...
*January 26, 2016*

**Physics**

You need how far it rolled down the hill to get initial speed v = w r where w is omega, the angular velocity kinetic energy = m g h = (1/2)I w^2 + (1/2) mv^2 = (1/2)(2/3)mr^2v^2/r^2 + (1/2)mv^2 =(mv^2/2)[2/3 + 1] = (5/3) (mv^2/2) so g h = (5/3)(v^2/2) solve for v, initial ...
*January 26, 2016*

**math**

If those are matrices, no they do not necessarily commute
*January 26, 2016*

**Physics**

Your equations seem to indicate that the 70 degrees is with the FLOOR, not the Wall, which makes more sense) First, force up = force down so force up at floor = 160 Call friction force at floor Fw It is equal and opposite to horizontal force at top Now moments about ladder at ...
*January 26, 2016*

**physics**

How amusing - you happened upon a Naval Architect. increased volume of ship in the water = Area * .025 meters mass of water displaced = density of seawater * that volume density of seawater is about 1029 kg/m^3 so mass of water displaced = 1029 * .025 * A Buoyancy force due to...
*January 25, 2016*

**physics**

You mean (4/3) pi r^3 r = 0.25 meter V = .0654 meters^2 mass of water displaced-mass of foam = (1000-300)(.0654) = 45.8 kg
*January 25, 2016*

**physics**

rho fresh = 1000 kg/m^2 rho salt = 1029 kg/m^3 approx submerged draft = d vol of block = .1*.1*.1 = .001 m^3 mass of block = 700*.001 = .7 kg volume of fresh water displaced must have mass = .7 kg so .1 * .1 * d * 1000 = .7 kg d = .07 m = 7 cm so freeboard above water = 3 cm ...
*January 25, 2016*

**Physical Science**

h = 4.9 t^2 h= 4.9(1.16)^2 h = 6.19 m
*January 25, 2016*

**physics**

assume salt water density = 1029 kg/m^3 and g = 9.81 m/s^2 mass in salt water = 1029*.8*60 = 1000 * d * 60 d = .8 (1029/1000) = .8232 m
*January 25, 2016*

**History**

Knowing nothing of the subject all I can do is give you a link: http://www.geocities.ws/krysstravel/writing_kanarda.html
*January 25, 2016*

**math**

7 = 1+6 2+5 3+4 if greater than 40 and less than 50, has to start with 4 impossible to be an even number 43
*January 25, 2016*

**math**

but if being strict about significant figures you only have two 5.1 * 10^6
*January 25, 2016*

**Calc help!**

What you typed does not make sense. Perhaps you mean: [ x(x+3) - (x+1)(x-3)] / (x^2-9) ??? [ x^2 + 3x - x^2 +2 x + 3 ] /(x^2-9) (5x+3)/(x^2-9)
*January 25, 2016*

**physics**

None, no motion in the direction of the force.
*January 25, 2016*

**I did this already**

http://www.jiskha.com/display.cgi?id=1453734257
*January 25, 2016*

**Math**

7 in ( 5 miles/1 in) = 35 miles
*January 25, 2016*

**Math**

same way as the one above (15 mi)
*January 25, 2016*

**Math**

yes
*January 25, 2016*

**Math**

24 + 36 + 24 + 36
*January 25, 2016*

**Physics**

99.5-.7 = 98.8 so Reading C = Cr = .7 +(98.8/100) C if Cr = 30 30 = .7 + .988 C C = 29.7 if the same C = .7 + .988 C .012 C = .7 C = 58.3 degrees C or Cr
*January 25, 2016*

**Math**

I assume you mean a = 6.25 m/s^2 Please proof read what you type. v = a t = 6.25 m/s^2 * 7 s = 43.75 m/s Now parachute, a = - 2.5 m/s^2 and Vi = 43.75 m/s v = Vi + a t 0 = 43.75 - 2.5 t t = 17.5 seconds
*January 25, 2016*

**math**

30 km (1 hour/225 km) = .1333333... = (.1 + 1/30) hours .1 hours = .1*60 minutes = 6 minutes (1/30) hours (60 min/hour) =2 minutes 6 + 2 = 8 minutes
*January 25, 2016*

**math**

70 km/h * 1000 m/km * 1 h/3600 s = 19.44 m/s so 50 km/h = 13.89 m/s a = change in v/change in t = (13.89 - 19.44)/5 = - 1.11 m/s^2
*January 25, 2016*

**Algebra**

well, halfway between x axis intercepts is x = 12/2 = 6 so that is where the vertex must be y - b = (x-6)^2 -5 - b = (-7)^2 = 49 b = -54 y = (x-6)^2 - 54 y = x^2 - 12 x + 36 - 54 y = x^2 - 12 x - 18 ===================== check: x^2 - 12 x = y+18 x^2 - 12 x + 36 = y+ 54 (x-6)^2...
*January 25, 2016*

**math**

The top seems to be an arithmetic sequence and the bottom a geometric sequence, but I can not get that ratio to converge as i --->oo
*January 25, 2016*

**maths**

6 n + 4/n = 14 ??? 6 n^2 + 4 = 14 n 6 n^2 - 14 n + 4 = 0 3 n^2 - 7 n + 2 = 0 (3n-1)(n-2)= 0 n = 1/3 or 2 which do you think? Hint - try 2 then try 1/3 :)
*January 25, 2016*

**Physics**

work accomplished = 300*30 = 9,000 J applied work = 9,000 + 2,000 = 11,000 Joules efficiency = 100 * work accomplished/work applied = (9/11)100 = 81.8 % force applied = (300/6)/.818 = 61.1 N assuming that the 6 in your question refers to mechanical advantage
*January 24, 2016*

**Algebra**

Yes, sure :) BUT you did not need to ask because to be sure just put it back in 2 (3) + 3 (2) = ??? maybe 12 6 + 6 = YES
*January 24, 2016*

**algebra**

if + k is to the right, it is everything left of but not including -1 if k is up, it is everything below -1
*January 24, 2016*

**Algebra**

well, pick any old x, like for example x = 0 find y 0 - y = 9 y = -9 so (0 , - 9) now pick another x, like x = 1 3 - y = 9 y = 3-9 = -6 so ( 1 , - 6 ) and on and on until bored
*January 24, 2016*

**math**

I assume you mean compounded r = interest rate specified usually per year /4 because compounding every quarter year 18.5 years * 4 = 74 periods 3 = x^74 log 3 = 74 log x log x = .00644758 x =1.015 so 1.5 percent per period or r = 4*1.5 = 6%
*January 24, 2016*