Monday

January 23, 2017
Total # Posts: 28,866

**math**

If you subtract nothing from twenty you still have twenty.

*August 24, 2016*

**physics vectors**

x direction: 6 a - 8 b + 25 = 0 y direction: -8 a + 3 b + 22 = 0 ========================== 24 a - 32 b + 100 = 0 -24 a + 9 b + 66 = 0 -------------------------add - 23 b + 166 = 0 b = 7.22 a = 5.46 check my arithmetic !

*August 24, 2016*

**MATH**

LOL, yes :) good

*August 24, 2016*

**MATH**

http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html Xn = a +(n-1)d 96 = a + 13 d 173 = a + 24 d --------------- -77 = -11 d d = 7 then a = 96 - 13*7 = 5 so X19 = 5 + 18*7 = 131 etc

*August 24, 2016*

**pre calculus honors**

try a. 10+2+3 = 15 yes 70+2+3 = 75 yes 30+2-3 = 29 yes so a works, the end :)

*August 24, 2016*

**MATH**

well, a = 6, given and d = 7 given Xn = 6 + (n-1)7 X6 = 6 + 5*7 = 41 X15 = 6 + 14*7

*August 24, 2016*

**MATH**

Now you did the one above, you can do this one.

*August 24, 2016*

**pre calculus honors**

but I cheated. [ used a = dV/dt = d/dt (dx/dt) ]

*August 24, 2016*

**pre calculus honors**

which is the acceleration of gravity on earth in ft/s^2 and indeed it works ;)

*August 24, 2016*

**pre calculus honors**

I wonder if a comes out -32 ft/second^2 :)

*August 24, 2016*

**typo I think not 12 but 1/2**

You mean s = (1/2) at^2 + v (small o) t + s (small o) so 161 = .5 a + Vo + So 98 = .5 a(4) + 2 Vo + So 3 = .5 a(9) + 3 Vo + So or 1 a + 2 Vo + 2 So = 322 2 a + 2 Vo + 1 So = 98 4.5a+ 3 Vo + 1 So = 3 solve three linear equations for a, Vo So

*August 24, 2016*

**math**

upwind speed = u -w downwind speed = u+w 1650 = (u-w)(3.3 hours) 1650 = (u+w)(3) 3 u + 3 w = 1650 3.3 u - 3.3 w = 1650 3.3 u + 3.3 w = 1.1*1650 = 1815 3.3 u - 3.3 w = 1650 -------------------- add 6.6 u = 3465 u = 525 miles/hour now find w

*August 24, 2016*

**Physics**

let g = 9.8 m/s^2 weight = 2500 * 9.8 = 24,500 N Thrust - weight - drag = m a 29,000 - 24,500 - drag = 2500 (1.7) drag = 250 N at this speed and thrust Now I do not know what your class has done about drag of a sphere. However what is needed is the speed at which the drag of ...

*August 24, 2016*

**Math**

f = 3 s + 4 f = 40 so 40 = 3 s + 4

*August 24, 2016*

**algebra**

I am doing the second part first :) x^a * x^b = x^(a+b) and x^-a = 1/x^a therefore x^7 * x^-2 = x^7/x^2 = x^5 or x^7 * x^-2 = x^(7-2) = x^5 remarkable :) x^7 / x^2 = x^7 * x^-2 which we already did :)

*August 23, 2016*

**math**

405 / 15 = x/1 15 x = 405 x = 405/15

*August 23, 2016*

**Physical science check my answers**

A is correct, and I assumed you meant A and just forgot to hit Enter.

*August 23, 2016*

**Physical science check my answers**

I agree with them all.

*August 23, 2016*

**Physical science check my answers**

Yes they are.

*August 23, 2016*

**Physical science check my answers**

try # 4. again, Vx = dx/dt x = Xi + Vx t

*August 23, 2016*

**biology**

1. but ice floats. You can skate on it. 2. The water heats up slowly so the fish makes it to dusk when the sun goes down. 3. Yes, correct 4. Yes, correct

*August 23, 2016*

**math ASAP**

27/21 = 9/7 * 3/3 the others do not work

*August 23, 2016*

**math**

3*24

*August 23, 2016*

**world geography**

1. disagree 2. agree 3. agree 4. Irish is a folk and the parade is part of their culture :) I am not at all sure fast food is a habit of members of any particular religion! When it says "general population" it is not focusing on a particular folk.

*August 23, 2016*

**algebra 1**

yes equation would be c = 0.75 + 0.25 t

*August 22, 2016*

**math**

sin x/ cos x = tan x 3 - 4 tan^2 x = 3 - tan^2 x tan x = 0 x = 0, pi etc

*August 22, 2016*

**Medical dosages - no idea**

I do not know what your acronyms mean.

*August 22, 2016*

**algebra 1**

You are welcome.

*August 22, 2016*

**algebra 1**

http://www.mathsisfun.com/definitions/quotient.html

*August 22, 2016*

**algebra 1**

Yes, when you see the word quotient you are talking about division.

*August 22, 2016*

**algebra**

v = 2.8 - 9.8 t v = 0 at top so t = .286 seconds rising at top h = 12 + 2.8 (.286) - 4.9 (.286)^2 = 12.4 meters how long to fall from 12.4 ? 0 = 12.4 - 4.9 t^2 t = 1.59 seconds to fall from up there so total time = .286+1.59 = 1.88 seconds

*August 22, 2016*

**Math**

x-1 = 1/x x^2 - x = 1 x^2 - x - 1 = 0 x = [ 1 +/- sqrt (1+4) ]/2 x = .5 +/- .5 sqrt 5 since it has to be positive x = .5 + .5 sqrt 5

*August 21, 2016*

**Math 2**

see above

*August 21, 2016*

**physics**

total time = 95/1.26 + 95/3.61 total distance = 95+95 average speed = total distance/total time

*August 21, 2016*

**Calculus**

V = x (30-2x)(20-2x) multiply that out Of course part 2 will be to take the derivative and set it to zero to find the height for maximum volume.

*August 21, 2016*

**physics .Henry,Damon,Steve,Saed,bobpursley, And This is my question every one**

back in his hands. It has the same horizontal velocity as the train has (ignoring air drag of course) Of course if the train speeds up while the ball is in the air, that changes it, but you can figure that out.

*August 21, 2016*

**physics .Henry,Damon,Steve,Saed,bobpursley, And This is my question every one**

Hey, why ask us? You know. In a vacuum, there is no difference, mass does not enter the equations. However if you include air drag, it is like you have a parachute attached. The lead ball will go further.

*August 21, 2016*

**LOL**

Do not see graph.

*August 21, 2016*

**physics .Henry,Damon,Steve,Saed,bobpursley, And This is my question every one**

a) do r(5) b) dx/dt = u = -12.3 + 4.86 t dy/dt = v = 3.6 t - .39 t^2 c) find sqrt (u^2+v^2) at t = 5

*August 21, 2016*

**PHYSICS ASAP REPLY**

A hydrogen filled balloon is lighter than air and rises. It can also burn very rapidly (Google Hindenburg) and it is safer to use helium even though it is not as buoyant.

*August 20, 2016*

**PHYSICS topic is pressure**

If you stay there long enough to decrease the oxygen and increase the CO2 and there is no input of fresh air that could happen.

*August 20, 2016*

**PHYSICS topic is pressure**

I do not have a lot of trouble breathing with SCUBA gear under 100 feet of water. The pressure there is far greater than that in any deep well full of air that I can imagine. Perhaps this well is full of water? I suppose the increased pressure by increased density of gas makes...

*August 20, 2016*

**typo error**

average speed crossing window = 20 m/s now look at increase of speed in 2 meter drop v = Vi + 9.8 (.1) call g = 10 for simplicity v = Vi + 1 but we know (v+Vi)/2 = 20 the average v = Vi + 1 v = -Vi + 40 -------------- 0 = 2 Vi -39 Vi = about 20 at top of window so how long did...

*August 20, 2016*

**Physics**

average speed crossing window = 20 m/s now look at increase of speed in 2 meter drop v = Vi + 9.8 (2) call g = 10 for simplicity v = Vi + 20 but we know (v+Vi)/2 = 20 the average v = Vi + 20 v = -Vi + 40 0 = 2 Vi -20 Vi = 10 at top of window so how long did it fall to the top ...

*August 20, 2016*

**Maths Unitary Method**

4*12 = 48 48 ban/104 RS (48 ban/104 RS)* 6.5 RS

*August 20, 2016*

**Maths Unitary Method**

(48 boxes/6000 pens) * 1875 boxes

*August 20, 2016*

**Maths Unitary Method**

(28/550)*700

*August 20, 2016*

**Math**

p = k sqrt r p^2 = k^2 r 3.2^2 = k^2 (4) so k^2 = 3.2^2/4 p^2 = (3.2^2/4)(6.5) find p^2 and take the square root

*August 19, 2016*

**computers**

I tend to agree, because based on the subject line I may or may not read the text itself. That also tends to make me decide if the thing is spam or not.

*August 19, 2016*

**Mathematics**

3 n - 5 n = 3.7 2 n = -3.7 n = -3.7/2

*August 19, 2016*

**Math**

g = b/3 b - g = 240 b - b/3 = 240 3 b - b = 720 2 b = 720 b = 360

*August 19, 2016*

**Math**

There are 11 + 9 = 20 children of those 20 children 11 are boys 11/20 = 55/100 = 55% of the children are boys Now you try the others.

*August 19, 2016*

**Maths Algebra**

speed down = v+2 speed up = v-2 5 (v-2) = 4 (v+2) 5 v - 10 = 4 v + 8 v = 18

*August 19, 2016*

**Science**

negative feedback. The increase in body temp caused a reaction (sweating) that counters the temperature increase. Positive feedback would be something that makes you heat up even more.

*August 18, 2016*

**math**

n^2 = 8281 n = sqrt (8281) 91 rows * 91 students/row

*August 18, 2016*

**Math- Geometric solutions and problems RIA**

I. is 200 *2^n if n = 5, then 200 * 32 II. 2^4 = 16 times as much every hour if it doubles every quarter hour 1500*16^6 (infinite :) III. a r^n + a r^n+1 + a r^n+2 = 70 or a r^2 (1 + r + r^2) = 70 4 a r^n + 5 a r^n+1 + 4 a r^n+2 is arithmetic so 5a r^n+1 - 4a r^n = d 4a r^n+2...

*August 18, 2016*

**Science**

I agree.

*August 18, 2016*

**Mechanics**

y = x^2 = x * x cm * cm or cm^2 So it is not correct. It is probably a typo or they just mean that lengths are in centimeters, leaving you to figure out that area is therefore in square centimeters.

*August 18, 2016*

**algebra**

Hey, Bob Pursley answered this hours ago.

*August 18, 2016*

**algebra**

x^2 + 1 = 2 x x^2 -2x + 1 = 0 (x-1)(x-1) = 0 so x = 1 x^anything = 1 and 1 + 1/1 = 2

*August 18, 2016*

**Chemistry**

35 x + 37(1-x) = 35.5 -2 x = -1.5 x = .75 1-x = .25 three times as much 35

*August 18, 2016*

**number theory**

http://www.jiskha.com/display.cgi?id=1471506858

*August 18, 2016*

**math**

yes, cool :)

*August 18, 2016*

**math**

g = sin^2(3T) dg/dT = 2 sin(3T) (3) cos(3T) = 6 sin (3T) cos(3T)

*August 18, 2016*

**Maths Algebra**

12.75 * 10^-6 and 7 * 10^-6 well 7 is about half of 13

*August 17, 2016*

**Math**

Maybe it means log base b of a^2=c That means 2 logb (a) = c or logb(a) = c/2 which means b^(c/2) = a can you take the log of a negative number?

*August 17, 2016*

**physics**

ok :)

*August 17, 2016*

**physics**

total east = -140 + 250 sin 45 + 280 sin 30 = 176.78 total north = 0 -250 cos 45 +280 cos 30 = 65.71 I do not understand where you get that last x and y in my opinion you must go west 176.78 and south 65.71 tan^-1 65.71/176.78 = 20.4 deg south of west

*August 17, 2016*

**Physics**

2 pi R/T = 1670 km/hour

*August 16, 2016*

**Science**

find a average speed = (15+7)/2 = 11 m/s so t = 88/11 = 8 seconds so a = (7-15)/8 = - 1 m/s^2 v = Vi + a t 0 = 7 - 1 t t = 7 during final stop d = Vi t + (1/2) a t^2 d = 7*7 - (1/2)49 d = 49/2 = 24.5 meters

*August 16, 2016*

**math**

(8/5)2000

*August 16, 2016*

**Algebra**

2 1/4 = 9/4 (9/4)/3 = 3/4 3/4 * 12 = 9 inches

*August 15, 2016*

**Social Studies**

That is an interesting choice but I disagree.

*August 15, 2016*

**math**

Horse named friday?

*August 15, 2016*

**physics**

h = (1/2) g t^2 = 4.9 *9 or about 45 meters

*August 15, 2016*

**Science(help please)**

Google !!!!

*August 15, 2016*

**Physics**

a = dv/dt = (31-15.3)/5 = 3.14

*August 15, 2016*

**math**

x and x+25 x^2 + x^2 + 50 x + 625 = 2425 cm^2 2 x^2 + 50 x - 1800 = 0 x^2 + 25 x - 900 = 0 (x-20)(x+45) = 0 x = 20 x+25 = 45

*August 15, 2016*

**Science**

plant growth depends on light when you vary the independent variable, light, the dependent variable , growth, changes. I would conclude that the plant needs water and light. Of course I assume they were both in the same soil with all essential nutrients.

*August 14, 2016*

**sorry**

I did not notice the second part. L * w = 68200 2 L + 2 w = 1460 L = 730 - w (730-w)w = 68200 730 w - w^2 = 68200 w^2 -730 w + 68200 = 0 w = [ 730 +/- sqrt(532900-272800)]/2 w = [730 +/-510 ]/2 w = 110 or 620 L = 620 and w = 110

*August 14, 2016*

**idea**

L * w = 68200 however unless you know more about the ratio of L to w, there are an infinite number of solutions.

*August 14, 2016*

**Math**

7 quarters/8 dimes is not 8 dimes / 7 quarters

*August 13, 2016*

**Help- Precalc**

since sin α < 0 α is in quadrant 3 or 4 since tan α is +, that puts α in quadrant 3 -5,-7, sqrt 74 triangle since csc β > 0, β is in quadrant 1 or 2 since cot β is -, β is in quadrant 2 -3, 5, sqrt 34 triangle now sin (a-b) = sin a...

*August 13, 2016*

**Math**

a-b = 4 a^2-b^2 = 80 (a-b)(a+b) = 80 4 (a+b) = 80 a+b = 20 a-b = 4 ------------ add 2 a = 24 a = 12 so b = 8

*August 13, 2016*

**physics**

v = g t = 9.81 t at t = 9, v = 9.81 * 9 at t = 10, v = 9.81 * 10 average speed during tenth second 4.9 (19) distance during tenth = 4.9 * 19 * 1

*August 13, 2016*

**Use parentheses**

I do not know what are your numerators and denominators.

*August 12, 2016*

**car rental agency**

a is 60 + .22 x b is 56 + .26 x when does 60 + .22 x = 56 + .26 x .04 x = 4 x = 100 miles

*August 12, 2016*

**Algebra 1**

http://www.dictionary.com/browse/irrational--number

*August 12, 2016*

**Better**

2 sqrt 5 = sqrt 20 sqrt 5 = 2.236067977 IRRATIONAL

*August 12, 2016*

**propability**

By the way I am assuming that death is a failure ;)

*August 12, 2016*

**propability**

4/20 = 2/10 = 0.2 Ik versta wel.

*August 12, 2016*

**physics**

Mass does not change with g, weight does. You seem to be using feet/pounds units so g = 32 ft/s^2 approx on earth Mass = 150 /32 slugs g other = 32 * (34/15)

*August 11, 2016*

**Science -Please answer**

I think your control is no cleanser.

*August 11, 2016*

**Trigonometry**

tan (angle) = 20/12 so angle = tsn^-1 (20/12)

*August 11, 2016*

**Science 1 question help plz thank you**

Basing a conclusion on too little data is not an ethical error but a scientific planning and execution error. Google ethical definition eg: http://www.dictionary.com/browse/ethics

*August 10, 2016*

**Pre algebra**

well, look at it here and there x always left of y on number line x=-2 y=-1 -> x-y = -1 and |x-y|=1 x= 8 y= 10 -> x-y = -2 and |x-y|=2 in fact if x < y then x-y is ALWAYS - and |x-y| = y-x so I conclude y-x

*August 10, 2016*

**check my spanish 3**

Do I have to write a sentence with it or can I just state the verb?? Sorry, it's a stupid question but I just want to make sure I'm correct

*August 9, 2016*

**check my spanish 3**

escriba la forma del verbo indicado en el tiempo indicado yo/ tener/ futuro My answer is tendré

*August 9, 2016*

**math**

163.50 ( 6/11 ) = 88.18

*August 9, 2016*

**math**

3*7*11 = 231 and 2+3+1 = 6 so that does it, 231 ====================== three times that would have a sum of 18 so 3*231 = 693

*August 9, 2016*