Tuesday

June 28, 2016
Total # Posts: 26,397

**calculus**

a = -9.8 v = Vi - 9.8 t h = Hi + Vi t +(1/2) a t^2 h = 2300 + 0 t - 4.9 t^2 = 2300 - 4.9 t^2
*April 7, 2016*

**calculus**

v = vi - a t 0 = 7 - 9.8 t t = 7/9.8 at top when v = 0 h = 3 + 7 t - 4.9 t^2
*April 7, 2016*

**physics**

frequency proportional to sqrt(g/L) g proportional to mass of planet and 1/r^2 g planet = g earth * 1.75/6.25 = .28 sqrt gplanet = sqrt gearth =.529 so frequency is .529 tht on earth period = 1/f so 1.6/.529 = 3.02 seconds
*April 7, 2016*

**calculus**

d^2y/dx^2 = x^2 dy/dx = (1/3)x^3 + c 8 = 0 + c so c = 8 or dy/dx = (1/3)x^3 + 8 y = (1/12)x^4 + 8 x + k 8 = 0 + k so k = 8 y = (1/12)x^4 + 8 x + 8
*April 7, 2016*

**Pre cal**

b = 12 / sin 55
*April 7, 2016*

**Math**

He ran more last week If he ran 6 miles last week then he ran 5 miles this week the 25 2/3 is just noise on the circuit all that matters is the 5/6
*April 7, 2016*

**Math**

Now that is quite enough ! 5/6 is LESS than ONE
*April 7, 2016*

**physics**

x = A sin 2 pi f t x = A sin 12.9 t v = dx/dt = 12.9 A cos 12.9 t v = 1.9 = 12.9 A cos 0 = 12.9 A A = 1.90/12.9 = .147 meter
*April 7, 2016*

**English**

A traditional African marriage is advantageous for the man but not for the woman.
*April 7, 2016*

**Physics - urgent**

http://www.physicsclassroom.com/class/sound/Lesson-5/Closed-End-Air-Columns remember period T = wavelength/speed and f = 1/T = 350/wavelength here the lowest frequency is when .14 meter = half a wavelength so wavelength = .28 meter lowest f = 350/.28
*April 7, 2016*

**Pre cal**

49 + 16 = 65 so sqrt 65 which is about 8.062257748
*April 7, 2016*

**Science**

I did not bother to Google but your answers look correct to me.
*April 7, 2016*

**Physics**

The center of mass of the system continues at rest because there are no external forces on the system. cg at 0 forever m girl * distance from 0 = m plank * distance from 0 center of plank moves 3 to right if girl now 2 meters from CG of system to left 3*12.6 = 2 m m = 3 * 6.3...
*April 7, 2016*

**Physics**

I assume a short circuit so total voltage is 0 V = L di/dt + iR = 0 let i = I e^kt then when t =0, i = I di/dt = I k e^kt = k i V = L I k e^kt + I e^kt R = 0 L k + R = 0 k = -R/L but I bet you knew that so k = -130/50*10^-3 = -2.6*10^3 I = 12 so i = 12 e^-2.6*10^3 t 4.8/12 = ....
*April 7, 2016*

**Physics**

frequency is proportional to square root of tension f *sqrt (25) = 5 f
*April 7, 2016*

**Math**

it will be 1/8 times as large so small
*April 7, 2016*

**Math**

Evie, all your questions are the same if the numerator is bigger than the denominator, the fraction is bigger than one 4/3 is bigger than one so MORE
*April 7, 2016*

**math**

30 ft (1 m/5280 ft) = .00568 mile v = .00568 /T in hours T in hours = .00568 /v T in seconds = 3600*.00568/v = 20.45/v clicks/second = 1/T = v/20.45 so v = 20.45 * clicks/second 1 click/second --> 20.45 mph 2 clicks/second -->41 mph v = 20.45 * clicks/second = clicks/20....
*April 7, 2016*

**Math**

2/5 is less than 5/5
*April 7, 2016*

**Math**

(5/4)w * w = 180
*April 7, 2016*

**science**

total y momentum = 0 m * 1.5 sin 30 = m v sin T so v sin T = 0.75 total x momentum = 2 m 2 m = 1.5 m cos 30 + m v cos T v cos T = .7 v sin T/v cosT = tan T = .75/.7 T = 47 degrees v = .7/cos 47
*April 7, 2016*

**Math**

L = 14 w/13 (14 w/13)(w) = 4800 w^2 = 13 (4800/14) w = 66.76
*April 7, 2016*

**English**

yes
*April 7, 2016*

**Physics 1**

potential energy loss = m g h = 3.08 * 9.8 * 1.27 = kinetic energy gain = (1/2) (1.95)v^2 + (1/2)I (v/r)^2 so what is v at the end of this experiment? find acceleration 1.27 = (1/2)a t^2 1.27 = (1/2)a (.83)^2 so a = 3.69 m/s^2 and v = a t = 3.69(.83) = 3.06 m/s at the end...
*April 6, 2016*

**i need help plz**

You, anyone, can copy a bit of it for just about any purpose - parody, comment, review, .... whatever
*April 6, 2016*

**slope**

well, check it and see.
*April 6, 2016*

**slope**

well, we know it is y = -4 x + b so all we need is b 5 = -4(9) + b 5 = -36 + b b = 41 so y = -4 x + 41
*April 6, 2016*

**History**

It stood officially for slave stealer, but abolitionists called it "slave savior".
*April 6, 2016*

**History**

Yes, got sick while sneaking slaves out. Slaves could not navigate and boat was taken and Walker arrested etc.
*April 6, 2016*

**History**

We can not tell. Gibberish. Reed is telling you you probably listed answers to another question. I told you south is wrong for sure. I am wondering if you are paying attention.
*April 6, 2016*

**History**

I do not know what Brace is being compared to but he shipped kids more from New York area West so not mostly southern.
*April 6, 2016*

**College Algebra/pre-calculus**

agree
*April 6, 2016*

**physics**

Be sure to check my arithmetic carefully !
*April 6, 2016*

**physics**

v = 6.58 so omega = 11 radians/second
*April 6, 2016*

**physics**

fell distance 4.05 so lost potential energy m g h = 3 * 9.81 * 4.05 That is kinetic energy of bucket plus spool v = omega R = .6 omega call omega = w Ke = (1/2) m v^2 + (1/2)I w^2 = (1/2)v^2 (m + I/.36) I = 5 * .5 * .36 = so I/.36 = 2.5 so 3 * 9.81 * 4.05 = .5 * v^2 *(5.5) ...
*April 6, 2016*

**Physics miscounted**

134.4
*April 6, 2016*

**Physics**

C = Q/v = 40*10^-6 Q = 40 * 10^-6 v i = dQ/dt = 40*10^-6 dv/dt let v = V sin wt dV/dt = V w cos wt so i = 40*10^-6 V w cos w t max i = 40*10^-6 V w w = 2 pi f = 2 pi(60) = 377 so max i = 40*10^-6 * 377 V so V = (2.26/(15080)) 10^6 =1344
*April 6, 2016*

**Math help please**

YOU MEAN sin^2 x=[ 1-cos(2x) ] /2 or 2 sin^2 x = 1 - cos(2x) cos 2 x = cos^2 x - sin^2 x so 2 sin^2 x = 1 - cos^2 x + sin^2 x sin^2 x = 1 - cos^2 x or sin^2 x + cos^2 x = 1 which is true
*April 5, 2016*

**Physics**

620 * .39 = x * 1.53 so (.39/1.53)620
*April 4, 2016*

**Algebra**

maybe you want: 3 7 2 3,7 3,2 7,2
*April 4, 2016*

**English**

Either but I would pick 2 because in the end the person, not the food, is supposed to be healthy.
*April 4, 2016*

**Math**

log3 (3m) log a + log b = log ab That is how a slide rule works. That is how old I am :)
*April 4, 2016*

**PHYSICS!!!**

ke at bottom = (1/2) m v^2 = (1/2) m (144) = 72 m Joules pe at top = m g h= m (9.81)(12.2 sin 18 = 37 m Joules so Lost 72-37 = 35 m Joules to friction Friction force = mu m g cos 18= 9.33 mu m work done by friction = 9.33 mu m * 12.2 = 114 mu m so 35 m = 114 mu m mu = 35/114...
*April 4, 2016*

**PHYSICS!!!!**

10 km/hr = 10/3.6 = 2.78 m/s 3 km/hr = 3/3.6 = .833 m/s 5 km at 10 km/hr --> 30 min which is 30 *60 = 1800 s energy = 700*1800 = 1.26*10^6 Joules 5 km at 3 km/hr --> 6,000 s 6,000 s * 300 w = 1.8*10^6 Joules ==============================
*April 4, 2016*

**Physics**

assuming that your potential energy is defined as zero at the bottom of the hill, all your energy is kinetic by the time you get there. 800 + 200 = 1000 Pert of this problem statement is missing though. In potentials, all you can define is differences. You have to define some ...
*April 4, 2016*

**Math**

2 pi r = 2 pi *7 = 14 pi inches
*April 4, 2016*

**PHYSICS!!**

change in potential energy = m g h = 2219*4*sin 30 = 4438 Joules = (1/2)mv^2 + (1/2)I w^2 but w = v/r = v/.4 = 2.5 v so 4438 = (1/2)(226)v^2 + (1/2)(22.6)(6.25 v^2) or 4438 = 184 v^2 so v = 24.2 m/s and w = 60.4 radians/s Torque * angle = change in Ke T * 2 pi = (1/2) I w^2
*April 4, 2016*

**PHYSICS!!**

first mass of rubber = 2000 * .3 * ∫ 2 pi r dr from r = .2 to r = .4 = 600 (2 pi) (1/2)(.16-.04) = 226 kg 226 * 9.81 = 2219 Newtons weight I = 2000*.3 *∫ 2 pi r^3 dr = 3770 (1/4)(.4^4-.2^4) = 22.6 ===================
*April 4, 2016*

**PHYSICS!!**

time = 100 * 3600 = 3.6 * 10^5 s so energy used= 120*3.6*10^5 = 432 * 10^5 Joules = m g h = 65 * 9.81 * h so h = .677 * 10^5 = 67,700 meters
*April 4, 2016*

**Math**

but 24 inches = 2 feet so r = 1 foot (4/3) pi (1)^3 = 4.19 ft^3 by the way 4/3 x 3.14/1 = 1.395 is wrong --- should be 4.19
*April 4, 2016*

**Math**

3/4 = .75 3/8 = .375 which is bigger?
*April 4, 2016*

**Math**

2(3.14 x 0.25) + 2(3.14)(.5)(4) answer in feet^2
*April 4, 2016*

**no**

You have to use all feet or all inches r = 0.5 feet NOT 6 inches
*April 4, 2016*

**math**

s + (s+30) = 36 2 s = 6 s = 3 f = 33
*April 4, 2016*

**Math-soh cab toa**

sin 30 = h/70 but we all know sin 30 = 1/2 so 35
*April 4, 2016*

**Physics**

final angular momentum about axis of rotation = initial angular momentum initial ang mom = 78*1.6 * 2 = 250 kg m^2/s final ang mom = 78 (2)^2 omega + 651 omega omega ( 963) = 250 omega = .26 radians/second
*April 4, 2016*

**History**

I would have chosen B A ---- interchangeable parts, came before assembly lines for example in weapons manufacture (Colt in Connecticut for example)
*April 4, 2016*

**History**

I suppose I have to agree, but we lost our forests here in Massachusetts to farming and wood stoves long before we had woolen mills and Springfield rifles. The really tall pines of course were marked with broad arrow symbols and reserved for the king's masts.
*April 4, 2016*

**Hard math question**

suspect 1 * 2 * 4 = 8
*April 4, 2016*

**Engineering science**

oh and for time avergae speed = 6/2 = 3 m/s so t = 4/3 seconds
*April 4, 2016*

**Engineering science**

normal force = m g cos 25 friction force = mu m g cos 25 = force down slope = m g sin 25 so sin 25/cos 25 = tan 25 = mu = .466 =================== at 10 degrees friction force = .466 m g cos 10 = .459 m g work done by friction = .459 m g d = loss of kinetic energy = (1/2)m(36...
*April 4, 2016*

**Math**

anything with straight sides and pointy top has volume = (1/3) height * base area so 1/3
*April 3, 2016*

**trigonomentry help!!!**

(x-q)(x-4q) = a x^2 + b x + c x^2 - 5qx + 4 q^2 =a x^2 + bx + c if a = 1 b = -5 q c = 4 q^2 then 4 b^2 = 100 q^2 and 25 a c = 100 q^2 and 100 q^2 -100 q^2 = 0 all right
*April 3, 2016*

**chem**

Mg + 2 HNO3 → Mg(NO3)2 + H2
*April 3, 2016*

**Math**

Perhaps you meant 0.15 % ?????
*April 3, 2016*

**Math**

55 = .15 x x = 366 2/3 which is about 367 :)
*April 3, 2016*

**Geometry**

rectangle is (53 + 6) by (55 + 6) or 59 by 61 2*59 + 2*61
*April 2, 2016*

**algebra**

I gues you are looking for a straight line of slope m = 3 through the point (4,5) y = 3 x + b 5 = 3*4 + b 5 = 12 + b b = -7 so y = 3 x - 7
*April 2, 2016*

**computer science**

I guess I would let n = 0 and y = 0 then I would say n = n+1 y = 12 * n if y > 30 go to the end immediately and stop then I would store and print y go back to that n = n+1 stop and end
*April 2, 2016*

**Math**

e^cos t = value at t - value at pi = value at t - e^cos pi but cos pi = -1 so e^cos t = value at t -e^-1 or e^cos t = value at t - 1/e so value at t = 1/e + e^cos t ------------------- now do value at t - value at 0 value at 0 = 1/e + e^1 = 1/e + e value at t = 1/e + e^cos t ...
*April 1, 2016*

**science**

work done = increase in kinetic energy = (1/2) m (V2^2-V1^2) V2 = 72/3.6 meters/second V1 = 54/3.6 meters/second m = 1500 kg then answer will be in Joules
*March 31, 2016*

**physics**

distance from each = d = sqrt(5^2+12^2) = 13 cm = .13 meter however we may notice that the component along the bisector will be zero due to the opposite signs of the charges. However that is no true of the component along the direction between charges E = k q/.13^2 for each ...
*March 31, 2016*

**Science**

http://en.wikipedia.org/wiki/Electromagnet
*March 31, 2016*

**Science**

the B field strength is proportional to the number of turns.
*March 31, 2016*

**Mathematics**

Looks like a typo problem to me the original was probably round to the nearest thousand dollars, 2000
*March 31, 2016*

**math**

Well done :)
*March 31, 2016*

**math**

Good :)
*March 31, 2016*

**math**

You are welcome, but more importantly do you know how to tell a straight line from a parabola or an exponential now?
*March 31, 2016*

**math**

You typed y = 5x, look up above. I found it correct in one of your earlier postings.
*March 31, 2016*

**AHHH!! NO**

Look, they are asking you which of these is a straight line with constant slope. In other words which looks like Y = m X + b That is B y = 19 x - 10 A, x^2 - 5 x - 14 is a QUADRATIC, parabola C, y = 5^x (NOT y = 5 x ) is exponential D, y = .03 x^2 etc is QUADRQATIC, parabola
*March 31, 2016*

**ah ha - you typed it wrong**

B)y = 19x – 10 C)y = 5^x NOT THIS. This is NOT 5 x as you wrote later.
*March 31, 2016*

**math**

There are two with constant slopes. B and C If you think there is only one answer, you have a typo.
*March 31, 2016*

**math**

B and C 19 and 5
*March 31, 2016*

**College Algebra**

the slope is -29 crimes per year In other words the number of crimes decreases by 29 every year. when t = 0, C = 31,000. That is the number of crimes when the equation started in 1998 I suspect the 31,000 is a typo as is the 29
*March 31, 2016*

**math**

the derivative is constant in B and C
*March 31, 2016*

**Physics**

334 * 2000 = 668,000 J
*March 31, 2016*

**Geometry**

x^2 + 10 x - 1200 = 0 (x-30)(x+40) = 0 x = 30 or x = -40
*March 31, 2016*

**Algebra 2**

3 150 4 150 + d 5 150 + 2 d = 180 so d = 30/2 = 15 month 1 = 150-30 = 120 An = 120 + (n-1)15 A12 = 120 + 11(15) = 285 yes correct 500 = 120 + (n-1)15 n - 1 = 25.33 n = 26.33 yes, 27
*March 31, 2016*

**math**

I guess A is at center and AB bisects CD ???? we need to know angle at center cos (T/2) = 4/5 T/2 = 36.9 degrees T = 73.7 degrees so area = (73.7/360) pi R^2
*March 31, 2016*

**physics**

horizontal speed = u = 50 cos 37 t = 80/u then how high is it at t h = (50 sin 37) t - 4.9 t^2 then d = sqrt (80^2 + h^2)
*March 31, 2016*

**math**

http://davidmlane.com/hyperstat/z_table.html
*March 31, 2016*

**math**

http://davidmlane.com/hyperstat/z_table.html
*March 31, 2016*

**Algebra 2**

d = -27 + 22 = -5 -7 - 5 = -12 -12 - 5 = -17 -17 - 5 = -22 so the last one on the list
*March 31, 2016*

**Math - Slope intercept**

sure looks like it to me. They asked the same question twice. I bet they meant to say: Write the equation in standard form 6 x - 3 y = 2 then solve for y in slope intercept form but who knows
*March 31, 2016*

**luthayi high school. science**

http://www.nlm.nih.gov/medlineplus/ency/article/002680.htm
*March 30, 2016*

**This is a trick question**

Velovicy is a VECTOR north one way, south back 31 lengths, 30 of which were back and forth so went 50 meters total north in the end How long did it take? 31 * 50 = 1550 meters back and forth at 900 m/3600 s time = 1550 *3600/900 = 6200 seconds so 50 meters/6200 seconds = 0....
*March 30, 2016*

**physics**

I will do position last a = dv/dt so a = -10*10^7 t + 3*10^5 zero at t = 3/10 * 10^-2 = .003 seconds a is positive for the whole .003s find v at t = .003 for part c x = integral v dt with x = 0 at t = 0 so x = (1/3)(-5.00×10^7)t^3 +(1/2)(3.00×10^5)t^2 length of ...
*March 30, 2016*

**physic**

k = 20 N/.098 m = 204 N/m m = 20/9.81 = 2.04 kg omega = w = sqrt (k/m) radians/second so w = sqrt (204/2.04) = 10 rad/s if x is distance from equilibrium position, positive up x = -.05 cos 10 t
*March 30, 2016*

**but**

You may not care about order withing each committee so perhaps you mean combinations, not permutations C(8,5) = 8! /[ 5! (8-5)! ] = 8*7*6/[3*2] = 56
*March 29, 2016*

**Geometry**

w L = 500 L = 5 w/4 w(5w/4) = 500 w^2 = 400 w = 20 L = (5/4)20 = 25
*March 28, 2016*