Thursday

February 11, 2016
Total # Posts: 25,210

**SOCIAL STUDIES**

So I guess you abandoned A and chose C ?
*December 16, 2015*

**Math**

area goes as square of scale ratio 24 (9/4)
*December 16, 2015*

**Maths**

tan 54 = h/51
*December 16, 2015*

**Mathematics**

x^2 - (a+b) x + a b - k^2 = 0 x = [(a+b) +/- sqrt { (a+b)^2 -4(ab-k^2)} ]/2 if (a+b)^2 -4(ab-k^2) is positive, there is no complexity = a^2 + 2 ab +b^2 -4ab + 4k^2 = a^2 -2ab + b^2 + 4 k^2 = (a-b)^2 + 4 k^2 BOTH of those terms are positive being squares of real numbers, whew ...
*December 16, 2015*

**physics**

90,000 meters / 3600 seconds = 25 m/s=Vi v = Vi + a t 0 = 25 + a t so a t = -25 and t = -25/a d = Vi t + .5 a t^2 50 = 25 (-25/a) + .5 a (625/a^2) 50 = -625/a + .5 (625/a) 50= -625/2a 100 a = -625 a = -6.25 then F = m a
*December 16, 2015*

**math**

2w+2L = 18 w+L = 9 8 and 1 ---> 8 7 and 2 ---> 14 6 and 3 ---> 18 5 and 4 ---> 20 note - the closer to a square, the bigger the area
*December 16, 2015*

**physical science**

v^2/r v = 2 pi r /T = 2 pi (3500/400) v = 55 m/s v^2/r = 55^2/3500 = .864 m/s^2
*December 16, 2015*

**phyics**

speed is 0 at the top so to get time to top 0 = Vi - 9.81 t Vi = 9.81 t then do height at that top t 4.8 = 1.2 + Vi t - 4.9 t^2 3.6 = 9.81 t^2 - 4.9 t^2 4.9 t^2 = 3.6 t = .857 second Vi = (9.81 ) .857 = 8.41 m/s
*December 16, 2015*

**Algebra**

slope = (7/10 + 1/5) / (1/4 - 2/3) = (7/10 + 2/10) / (3/12 - 8/12) = 9/10 / -5/12 = -54/60 / 25/60 = - 54/25 y = -(54/25) x + b 7/10 = -(54/100) + b b = 124/100 so y = -(54/25) x + 31/25 25 y + 54 x = 31
*December 16, 2015*

**science**

resistivity is a characteristic of material NOT GEOMETRY RESISTANCE is another story.
*December 16, 2015*

**science**

it varies the resistance. of course if the voltage is a constant, the current also changes
*December 16, 2015*

**Statistics**

.9 * 10 = 9
*December 16, 2015*

**A.V. M. Sr. sec. school faridabad**

The same typo question
*December 15, 2015*

**Nonsense**

This three times repeated question is worded incorrectly. Obviously either could do the job many times in 15 days
*December 15, 2015*

**Typo?**

I do not understand either.
*December 15, 2015*

**algebra**

y = m x + b when y= 0, x = 3 when x = 0, y = 2/3 so 2/3 = 0 + b or b = 2/3 y = m x + 2/3 then when y = 0 , x = 3 0 = m (3) + 2/3 m = - 2/9 so y = -2/9 x + 2/3 or 9 y = -2 x + 6
*December 15, 2015*

**4th grade Number patterns**

This is an arithmetic sequence see : http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html term n = a + d(n-1) a = 23 d = -2 term 7 = 23 -2 (6) = 11
*December 15, 2015*

**Physics**

Thrust - weight = m a Thrust = m g + m a a =( Thrust-mg ) / m a = Thrust/m - g a = 27/1.5 - 9.81 = 18 - 9.81 = 8.19 m/s^2
*December 15, 2015*

**Algebra**

v+c = 20/5 = 4 v-c = 20/8 = 2.5 ----------------------add 2 v = 6.5 v = 3.25 c = 4 - 3.25 = .75
*December 15, 2015*

**Algebra**

x-1/5 = 3 x = 3 1/5 = 16/5 -x+1/5 = 3 x = -14/5 C
*December 15, 2015*

**Algebra**

I do not understand the notation for #1 2 change in y is constant -5 for changes of 1 in x linear, down you are right D 3 right 4 .9n-.4 yes A
*December 15, 2015*

**physics**

let's say x = A sin w t v = A w cos w t a = -A w^2 sin wt = -w^2 x w = sqrt k/m but we do not really need to know that max potential energy = (1/2)k max x^2 = (1/2) k A^2 max kinetic energy = (1/2) m v^2 but max v^2 = A^2 w^2 so max ke = (1/2) m A^2 w^2 the max ke = max pe...
*December 15, 2015*

**Math**

no, the slope you got was 1.10 I suspect. Of course I do not see your data.
*December 15, 2015*

**Math**

all lengths scale with the scale ratio 10*6 = 60 when they ask for areas - they scale with the square of the ratio and volumes scale with the cube
*December 15, 2015*

**wrote converse wrong**

converse: if not a triangle, then four sides (maybe)
*December 15, 2015*

**Geometry**

I have to write this on my brain first: hypothesis: If a cow, then a mammal converse: If a mammal, then a cow (maybe) inverse:If not a cow then not a mammal(maybe) contrapositive: if not a mammal, then not a cow - TRUE ok, now Hypothesis: if 4 sides, then not a triangle ...
*December 15, 2015*

**Maths**

3 sin^2 T - sin T = 1/4 ???? let z = sin T 3 z - z = 1/4 z - z/3 = 1/12 z - z/3 + 1/36 = 3 /36 + 1/36 = 4/36 = 1/9 (z-1/6)^2 = 1/9 z = 1/6 +/- 1/3 z = 1/2 or z = -1/6 if sin T = 1/2 T = 30 degrees or pi/6 if sin T = -1/6 T = -9.6 degrees
*December 15, 2015*

**Physics**

2 rev * 2 pi radians/rev = 4 pi radians so omega = 4 pi radians / 1.9 seconds
*December 15, 2015*

**Physics**

g (change in h) = (1/2)v^2 or v = sqrt (2 g*change in h) (note - m is irrelevant. That is lucky or a full car would be faster than a light one)
*December 14, 2015*

**math**

in first year: 245,000 in second year 245,000 (1.15)^1 in third year 245,000 (1.15)^2 in nth year 245,000 (1.15)^(n-1) NOW - go to web site Math is fun and look upo geometric sequence with a = 245,000 and r = 1.15 it also shows you how to sum the first ten terms :) http://www....
*December 14, 2015*

**Physics**

http://www.jiskha.com/display.cgi?id=1450123171
*December 14, 2015*

**Physics**

been there done that see calculus below
*December 14, 2015*

**Calculus**

well, let's find the vertex and intercepts. x^2 - 11 x = -y - 24 x^2 - 11 x + 121/4 = -y - 24 + 30.25 (x-11/2)^2 = -(y-6.25) so PN = 6.25 now what are A and B when y = 0 (x-11/2)^2 = 6.25 x-5.5 = +/- 2.5 x = 3 or 8 A is at 3 and B is at 8 so 2 PN * AB = 62.5 divide by ...
*December 14, 2015*

**Calculus, Physics**

http://www.jiskha.com/display.cgi?id=1450123171
*December 14, 2015*

**Calculus, Physics**

So you want me to do it three times?
*December 14, 2015*

**math answers??? correct me :/**

Yes
*December 14, 2015*

**Science**

You are welcome.
*December 14, 2015*

**Science**

Humm, not my thing but I think a predator would be a lion or something that eats the whole dog. This looks like a parasite to me, just living inside and feeding off the dog.
*December 14, 2015*

**Math**

so much to get on board plus so much per mile for example if the costs were one mile for $10 two miles for $15 then cost = m x + b 10 = m (1) + b 15 = m(2) + b -------------- subtract -5 = m - 2 m = - m so m = 5 then b = 5 so cost = 5*(miles) + 5 five to get aboard, + five per...
*December 14, 2015*

**Physics**

initial momentum right = m v - 2m*3v = -5 m v final momentum the same final mass = 3 m so 3 m Vfinal = - 5 m v Vfinal = - (5/3) v
*December 14, 2015*

**Physics**

Ah, no way a diver would be that poorly weighted but anyway .65 g/cm^3 = 650 kg/m^3 volume of diver = 100 kg/650 kg/m^3 = .154 m^3 buoyancy force on diver = .154m^3 * 1000 kg/m^3 * 9.81 = 1509 Newtons up diver weight down = 100*9.81 = 981 N so force up on spring = 1509-981 = ...
*December 14, 2015*

**Physics**

m g h = m C delta T so delta T = g h /C where C is specific heat of water.
*December 14, 2015*

**Physics**

Remember: In a car you can measure speed with a speedometer. but for velocity you need both a speedometer and a compass. Speed is the magnitude of the velocity vector, a scalar.
*December 14, 2015*

**Physics**

Both velocity and acceleration are vectors. Vectors have magnitude and DIRECTION. Their magnitudes may stay the same, speed may be constant tangential to orbit path and acceleration magnitude toward earth. HOWEVER The velocity and acceleration DIRECTIONS change constantly, so ...
*December 14, 2015*

**math**

e+4=c e-7 +c-7 = 22 e - c = -4 e + c = 36 -------------- add 2 e = 32 so e = 16 then c = 20
*December 13, 2015*

**math**

2 L + 2 w = 400 L + w = 200 L = w + 40 so w + 40 + w = 200
*December 13, 2015*

**science**

m1 (1/2) m 1 v^2 m2 (1/2) m2 (2v^2) = (1/2) m2 v^2 * 4 if the masses were the same, then 4 times
*December 13, 2015*

**Physics**

fall from 2 meters potential energy loss = m g h =.01 *9.81*2 = .1962 Joules kinetic energy gain = (1/2)mv^2 =.005(9) =.045 Joules difference is lost to heat .1962 - .045 = .151 Joules
*December 13, 2015*

**Math**

the race for smallest is between .09 and 1/8 now divide 1 by 8 and see what you get or divide .25 by two
*December 13, 2015*

**physics**

before East momentum = 22000 North momentum = 3000 v after East momentum = 5200 (5.16 cos 35) North momentum =5200 (5.16 sin 35) so 3000 v = 5200 (5.16 sin 35) solve for v
*December 13, 2015*

**Math**

I suspect you might mean 5^(x+4)=125^(1-3x) 5^(x+4)=(5^3)^(1-3x) 5^(x+4)=5^3(1-3x) (x+4) = 3 - 9 x 10 x = -1 x = -.1 ===================== or (x+4) log5 (5) = (1-3x) log5(5^3) (x+4) log5(5) = (1-3x)(3)log5(5) but log5(5) = 1
*December 13, 2015*

**Physics**

.4 = (1/2) k (.0375)^2
*December 13, 2015*

**Physics (angle Vector)**

cos (heading) = 5.4/11.8
*December 13, 2015*

**science**

heat in = 130 * .2 * 25 Joules
*December 13, 2015*

**Physics**

m g h = 35 * 9.81 * 5 Joules part B is negative part A
*December 13, 2015*

**math**

simple interest is the same every year so interest = 3900/8 = 487.50 per year (487.50/7500) 100 = 6.5 %
*December 13, 2015*

**Math**

You are welcome.
*December 13, 2015*

**Math**

just like if it were 50/100 as a percent = (1/2) * 100 = 50%
*December 13, 2015*

**Math**

(300/100) * 100 = 300 percent
*December 13, 2015*

**Structures**

delta L/L = F/area / E delta L = 144 in * 36*10^3 lb /5.5 in^2/1.3*10^6 = 725 * 10^-3 = .724 inches (scary! probably fails under buckling but we were not asked) )
*December 13, 2015*

**physics**

horizontal = 80 cos 60 vertical = 80 sin 60
*December 13, 2015*

**Physics**

height above bottom of swing = 1.75 *(1-cos 35) = .316 meters up so potential energy relative to bottom of swing = m g h = 22 (9.81)(.316) = 68.3 Joules (1/2) m v^2 = 68.3 so v^2 = 2 * 68.3 /22 v = 2.49 m/s loss = 68.3 - (1/2)(22)(2.2)^2
*December 13, 2015*

**physics**

Well, let's see how far down it went: sin 30 = h/3 so h = 1.5 meters high so at the top it has potential energy = m g h = 10*9.81*1.5 = 147 Joules compared to when it hits the ground. ------------------------------------- Let's look at the friction: weight = m g = 98.1...
*December 13, 2015*

**Physics**

-1.01 * 10^3 N = .144 a a = -7.01 * 10^3 m/s^2 v = Vi + a t at the end, v = 0 0 = 40.5 - 7.01*10^3 t so t = time to stop = 5.77 * 10^-3 seconds d = Vi t + (1/2) a t^2 = 40.5 * 5.77*10^-3 - 3.5*10^3 (5.77)^2 *10^-6 = 234 *10^-3 - 117*10^-3 = 117*10^-3 = .117 meteres
*December 13, 2015*

**Calculus**

There are two ways of thinking about this: 1. Straight math V = (4/3) pi r^3 dV/dr = 4 pi r^2 2. Common sense dV = surface area * dr dV = 4 pi r^2 dr anyway dV/dt = dV/dr dr/dt dV/dt = 4 pi (25) (.15) if D = 12 then r = 6 dr = dV/4 pi r^2 dr/dt = (1/4*36 pi ) dV/dt
*December 13, 2015*

**B/dar yes, physics**

F = m Ac = m v^2/R = 800 (100)/65 = 1231 Newtons
*December 13, 2015*

**Physics**

v = 22 22^2 = 484 the velocity is given as 22 m/s at the start I got the final velocity from the kinetic energy , the initial ke plus the amount gained in the fall
*December 13, 2015*

**Physics**

1. If you call the potential zero at ground level then at the start the projectile has: potential + kinetic = m g h + (1/2) m v^2 = 2.5 * 9.81 * 15 + (1/2)(2.5)(484) = 368 Joules potential + 605 J kinetic = 973 Joules total 2. we did that above, it is the loss in potential ...
*December 13, 2015*

**Physics**

m v = .01 * 1000 = 10 kg m/s
*December 13, 2015*

**PHYSICS( FRICTION)**

which at 2 and which at 8? assuming the small one is at 2 and the big one at 8 normal force = 9.81 N friction force = .4*9.81 = 3.92 N forward force on top small block = 3.92 a of small block = 3.92/1 = 3.92 m/s^2 so speed of small block = 2 + 3.92 t back force on big block...
*December 13, 2015*

**Physis**

There is no vertical problem here, no vertical motion final momentum = initial momentum = 0 horizontal speed of rock = 11.9 cos 36.8 so 14.8*11.9 cos 36.8 - 70.5 v = 0
*December 13, 2015*

**Math**

.75 w = 3900 so w = 3900/.75 = 5200 Liters
*December 13, 2015*

**maths**

A = Ao * (1/2)^(n/22) .8 = .5^(n/22) log .8 = (n/22) log .5 n/22 = .3219 n =7.08 years
*December 13, 2015*

**physics**

d = (1/2) a t^2 11 = (1/2) a (25) a = .88 m/s^2 so 80 = m (.88) m = 90.9 kg v = a t = .88*5 = 4.4 m/s which continues without force for five seconds so 4.4 * 5 = 22 meters more
*December 13, 2015*

**Physics**

force down = 600 force up = Fd 600 - Fd = m a = 61.2 * 7.6 so Fd = 600 - 465 Fd = 135 N so I agree with you
*December 13, 2015*

**Math**

500 = L + 2 w so L = 500 - 2 w Area = L w = (500 - 2 w)w = 500 w - 2 w^2 where is vertex of that parabola? 2 w^2 - 500 w = - A w^2 - 250 w = -(1/2) A w^2 - 250 w + 125^2 = -(1/2) A + 15625 (w-125)^2 = -(1/2)( A - 31250) so A = 31250 at vertx
*December 12, 2015*

**math**

x = 4-2y V = value =(4-2y)^2 + (4-2y)y - y^2 V = 16 - 16 y + 4y^2 + 4 y -2 y^2 -y^2 V = y^2 - 12 y + 16 so y^2 - 12 y = V-16 y^2 - 12 y + 6^2 = V - 16 + 36 (Y-6)^2 = V+20 vertex at v = -20
*December 12, 2015*

**physics**

Yes acceleration in m/s^2 /9.81 = number of g s
*December 12, 2015*

**No idea**

where these points are or why she is exerting 80 N on a pole that weighs about 50 N Is she holding it near and end - up with one hand and down with the other to balance weight and moments?
*December 11, 2015*

**Math**

You are welcome.
*December 11, 2015*

**Math**

start at the decimal and move right until you get one non zero number on the left, namely 5 You had to move right SIX spaces which is multiplying by ten six times so .00000512 * 10^6 = 5.12 so .00000512 = 5.12 /10^6 which is 5.12*10^-6
*December 11, 2015*

**Calulus**

ok first split it 4 e^x dx - 3 dx 4 e^x - 3 x evaluate at 6 and subtract the value at x = 1 ------------------------- or perhaps you mean 4 e^(x-3) dx then you have 4 e^(x-3) = 4 e^-3 e^x so integrate (4 e^-3) integral e^x dx which is just 4 e^-3 e^x or 4 e^-3 [ e^6 - e1 ]
*December 11, 2015*

**I do not understand**

what do you mean plus the number and do you mean integrate from x = 1 to x = 6 or what?
*December 11, 2015*

**Algreba**

2 * x^6 * 3 * x*(1/2) = 2 * 3 * x^6 * x^1/2 = 6 * x^(6 + 1/2) = 6 x^(12/2+1/2) = 6 x^(13/2)
*December 11, 2015*

**Geometry**

1. I disagree 2. isosceles vertex angle is 4x-3 other two are both x - 3 so (4x-3) + 2 (x-3) = 180
*December 11, 2015*

**Math**

2 x^2 - 4 x + c = 0 for real solution sqrt (4^2 - 4*2*c) must be real so 16 - 8 c must be positive so 8 (2-c) must be positive so c <= 2
*December 11, 2015*

**Physics**

sqrt (300^2 + 50^2)
*December 11, 2015*

**SCIENCE**

silver of course because it is a great conductor but perhaps if I did not own a silver mine I might choose copper which is pretty good but a bit less expensive. good insulator, like glass, but if it has to bend use plastic or rubber.
*December 11, 2015*

**maths (trigonometry)**

sqrt (225+64)
*December 11, 2015*

**maths**

lol 60 + 30 = 90 a right angle so the tower is the hypotenuse h^2 = 225 + 64
*December 11, 2015*

**probability**

p success = .91 p fail = .09 chances of missing zero + chances of missing one 4C0 = 1 so 1 * .09^4 * .91^0 = .09^4 = 6.56*10^-5 4C1 = 4!/[3!] = 4 so 4*.09^3*.91 = .00265 .00265 +.0000656 = .00272
*December 11, 2015*

**Mathematics**

x log 3 = log 7 x = log 7/log 3 unclear what is exponent 2 or 2x or 2x+1 use parentheses I will guess 4^(x-6) = 2^3x 2^2(x-6) = 2^3x so 2x-12 = 3x
*December 11, 2015*

**Math**

Find probability of rolling 12 which is 6 on both dice 1/6 * 1/6 It is (1 - that)
*December 11, 2015*

**Math**

tangent is not defined at x = 1. Slope is 2 on the left and 1.5 on the right.
*December 11, 2015*

**algebra 2**

http://www.mathportal.org/calculators/polynomials-solvers/polynomial-graphing-calculator.php note two real roots 1 2.383 two complex roots
*December 10, 2015*

**math**

f = 3 s f+12 = 2(s+12) 3 s + 12 = 2 s + 24 s = 12 f = 36
*December 10, 2015*

**Algebra**

6x+10y must be AT least 120, She would prefer more so 6x+10y >= 120 which is B
*December 10, 2015*

**Math**

15000/200
*December 10, 2015*

**Math**

I do not know any better than you do and suspect that they want you to say 3 although we both know that it can not quite be 3.
*December 10, 2015*

**Physics**

r = 3963 + 125 circumference of orbit = 2 pi r time = circumference /19700
*December 10, 2015*