Monday
February 8, 2016

# Posts by Damon

Total # Posts: 25,160

physics
g is -9.8 if up is positive The only time I did not use - is when the thing was falling. I knew I had - on both sides. I could have written - (h +19.6) = - 4.9 t^2 because it goes DOWN that distance with a negative acceleration starting at the tip top of its path.
December 20, 2015

physics
v = Vi - 9.81 t v = 0 at top so 0 = Vi - 9.81*2 Vi = 19.6 m/s up h = Vi t - 4.9 t^2 = 19.6(2) - 4.9(4) = 19.6 meters above roof then falls for 8 - 2 = 6 seconds from way up there h+19.6 = 4.9 (36) h = 157 meters, 50 stories high !
December 20, 2015

physics
40000/3600 = 11.11 m/s 15 m/11.11 m/s = 1.35 seconds to get to Porsche starting point time t from porsche start. Vp = 3 t xp from light = (1/2)3 t^2 t car = (t - 1.35) seconds xc from light = 11.11 (t-1.35) when does xp = xc ? 1.5 t^2 = 11.11 (t-1.35) 1.5 t^2 - 11.11 t + 15 = ...
December 20, 2015

Physics poweful diver
By the way 20 meters per second is quite a spring. Are you sure it is not 2 ? say you jump with a speed up of 20 m/s from the ground at top. I will call g = 10 instead of 9.81 0 = 20 - 10 t t = 2 seconds upward h = 5 t^2 = 5(4) = 20 meters that is like 20 yards 60 feet !!! ...
December 20, 2015

Physics
v = Vi - 9.81 t h = Hi + Vi t - 4.9 t^2 A. after .5 seconds: v = 20 - 9.81(.5) h = 5 + 20 (.5) - 4.9 (.25) B. 0 = 5 + 20 t - 4.9 t^2 solve quadratic equation for t when h is zero C. at top v = 0 0 = 20 - 4.9 t at top use t at top for height h = 5 + 20 t - 4.9 t^2 D. v = 20 - 8...
December 20, 2015

PHYSIS
omega = sqrt (k/m) so 2 pi f = sqrt (k/m) so 2 pi/T = sqrt (k/m) so 2 pi/ 6.60 = sqrt (k/53) solve for k then m g = k x x = 53*9.81/k
December 20, 2015

Math mystery
if it is equilateral why does it have three different side lengths?
December 20, 2015

math
a + a+d + a+2d = 3 a + 3 d = 3(a+d)=12+3d firat = 4 third = 4+2d 7th = 4+6d r and the geometric is b, br, br^2, br^3 ... 4 = b 4+2d = b r = 4r 4+6d = b r^2 = 4 r^2 so 2 d = 4 r - 4 or d = 2r-2 6 d = 4 r^2 -4 or d = (2/3)r^2 -2/3 2 r - 2 = (1/3) (r^2 - 1) 6 r - 6 = r^2 - 1 r^2...
December 20, 2015

maths
10 m (100 cm/m) = 1000 cm
December 20, 2015

physics
p = m v so v = p/m Ke = (1/2) mv^2 = (1/2) m (p^2/m^2) = (1/2) p^2/m
December 20, 2015

physics massive and momentous homework dump
Have you tried to do all these problems or do you just think I need the practice? momentum after = momentum before momentum is a vector so momentum in the x direction after = momentum in the x direction before and momentum in the y direction after = momentum in the y direction...
December 20, 2015

math
(5 miles/ 2 minutes )60 minutes = 150 miles I assume on a race track :)
December 19, 2015

Math
a y = -x + b y = -x/a + b/a
December 19, 2015

math
h = 9 - .5 t or if you insist on x and y y = 9 - .5 x (0,9) obviously (1,8.5) (2,8) (3,7.5) etc etc etc yes, there is one y for every x y = 9 - .45 x
December 19, 2015

science help PLS
Hey, I you squeeze it, it gets denser !
December 19, 2015

science help PLS
well, I do not think you need anything but imagination here but anyway if PV = n R T density proportional to n/V n/V = P/RT if T constant density goes down if pressure goes down
December 19, 2015

MATH HELP
F(t) = 6 t ? t is time or year F(6) = 6 * 6 = 36 Could you have a typo? Do you mean something else by 3(2) maybe 3^2 which is 9 but that would give 54 which is not a choice.
December 19, 2015

math
Surely the question was not worded that way. Do you mean assessed value of property? (8/12)(12300)(.16) = 1312 By the way a 16% tax rate is much, much higher than any I have ever heard of. No one would buy property there.
December 19, 2015

Math
II think you mean t^2 + 4 t + 30 v = 2 t + 4 a = 2 I do not know why you are supposed to know that if you are not taking calculus.
December 19, 2015

Math
Yes, that is the only one where he makes 200 or more
December 19, 2015

math
cups a cups is 8 ounces of water a pint is 16 ounces of water 8 cups is 4 pints a pint is a pound the world around (500 cm^3 of water (500 grams) is often called a pound :)
December 19, 2015

Physics (Heat)
Dry air moving over your skin causes evaporation from the surface which is cooling as well as brute force warming up if your skin is warmer than the moving air.
December 19, 2015

Math
2w+2L = 46 so w+L = 23 L = w+5 so w + w + 5 = 23 2 w = 18 w = 9 then L = 14
December 19, 2015

Mathematics
ab = 10 a + b a + b = 4 so b = (4-a) 10 b + a - 10 a - b = 18 - 9 a + 9 b = 18 -9 a + 9 (4-a) = 18 -18 a = -18 so a = 1 then b = 3 and the number is 13
December 19, 2015

Physics for
If you mean the spring force is F(x) = - k x^4 the force you have to exert is the negative of that then integral from x1 to x2 of integral-F(x) dx which is (1/5)k [ x2^5 - x1^5 ] = (1/5) k [ 1.35^5 - .73^5 ]
December 19, 2015

math
I do not know what specific level you are talking about. around third grade "Singapore Math" texts seem to be common, for example "Math in Focus" , The Singapore Approach, which you can find online for example: http://www.rainbowresource.com/prodlist.php?...
December 19, 2015

math
Ah, I think that is backwards. We learned our math from you (see Fibonacci). http://en.wikipedia.org/wiki/Fibonacci " Fibonacci popularized the Hindu–Arabic numeral system to the Western World[5] primarily through his composition in 1202 of Liber Abaci (Book of ...
December 19, 2015

Health 4 questions PLZ HELP MEEEEEEE
I told you what I thought.
December 18, 2015

Health 4 questions PLZ HELP MEEEEEEE
trans fats are cheap because easily manufactured but bad 2 agree 3 agree 4 it is the percentage of what you need of that nutrient that day (somebody says)D
December 18, 2015

health PLZ HELP ME ASAP
I believe so
December 18, 2015

health PLZ HELP ME ASAP
Nutrition Facts Peanut butter, smooth style Amount Per 2 tbsp (32 g) Calories 188 % Daily Value* Total Fat 16 g 24% Saturated fat 3.3 g 16% Polyunsaturated fat 4.4 g Monounsaturated fat 8 g Cholesterol 0 mg 0% Sodium 5 mg 0% Potassium 208 mg 5% Total Carbohydrate 6 g 2% ...
December 18, 2015

health PLZ HELP ME ASAP
check out peanut butter.
December 18, 2015

Social Studies
I did not see any in any of the Tolkien movies.
December 18, 2015

Social Studies
For some mysterious reason I had a lot of trouble finding Big Horn sheep in New Zealand links with google. I did find some New Zealand hunting outfitters that were ready and willing to send clients to Colorado though :)
December 18, 2015

NEED Math Help ASAP PLZ!!!
You are welcome.
December 18, 2015

NEED Math Help ASAP PLZ!!!
direct variation means y is proportional to x (if you double x, you double y) algebraically that means; y = k * x where k is a constant which they call "constant of proportionality" and I just call "k" :) here y = (-3) * x or -3x
December 18, 2015

Science
By the way tides are much more complicated than the explanation I just gave which is attributable to Isaac Newton himself. They are fundamentally a wave motion pulled around and around the earth by the interaction of earth and moon gravity. However in the deep open ocean they ...
December 18, 2015

Science
They would smooth out and there would be no diurnal motion of the water surface. Boring, like a lake :)
December 18, 2015

Science
Most of the diurnal tide motion is caused by the rotation of earth under the moon. The moon pulls hard on the part of earth closer to the moon, that is a high tide when you look up at the moon However you get a second high tide that day when the moon is on the opposite side ...
December 18, 2015

physics
m v^2/r = .7 m g or Ac = .7 g :) 39^2 / r = .7 (9.81) r = 39^2/ (.7*9.81)
December 18, 2015

PHYSICS
v = Vi + a t v = 0 when it stops 0 = 2.7 - .12 t y = 2.25 seconds to stop d = Vi t - (1/2) a t^2 = 2.7 * 2.25 - .5 * .12 * 2.25^2
December 18, 2015

Physics
friction force up slope = mu m g cos 30 work done by friction = -80 mu m g cos 30 drop in height = 80 sin 30 = 40 ft potential energy drop = m g (40 ft) ke = (1/2) m v^2 so (1/2)m(45)^2 = 40 m g - 80 mu m g cos 30 1012 = 40(32) - mu * 32 * 69.3 1012 = 1280 - 2218 mu mu = (1288...
December 18, 2015

Hey, try the problems. also be careful typing y-5/3=1 which is y = 8/3 is NOT (y-5)/3 = 1 which is y = 8
December 18, 2015

Math
0.9 * 59.99 = 53.99 5 * .035 * 660 = 115.50 agree
December 18, 2015

English
I agree with all four answers.
December 18, 2015

One more for Damon!
buy the pizza first 21.39 - 12.99 = 8.40 for the water 8.40/2.10 = 4 bottles or A
December 18, 2015

Math
2. 1y+1.2 y = 2.2 y so 2.2 y + 1.2 d 5. -3m + 3m + 18 = 0 + 18
December 18, 2015

Math
Hey, you asked for the average speed but you answered 8 8 is the speed OUTBOUND 24 km/3 hours = 8 8 is the speed out, not the average speed
December 18, 2015

Math
return trip took 4 hours at 6 km/h so d = 24 km (that must be to Guam from the harbor entrance buoy :) total round trip took 3+4 = 7 hours total distance = 24+24 = 48 km average speed = 48 km/7 h = 6.85 km/h
December 18, 2015

Math
Just put a 5 where I had a ? mark :) say distance d a to b time = 3 = d/v b to a time = 5 = d/(v-15) so d = 3 v and d = 5(v-15) 3 v = 5 v - 75 2 v = 75 v = 37.5
December 18, 2015

Math
outbound at speed v back at speed (v-15) say distance d a to b time = 3 = d/v b to a time = ? = d/(v-15) You did not give me all the information
December 18, 2015

Math
2.3960 = 2.3 + 0.096 + 0.0000 2.3965 = 2.3 + 0.096 + 0.0005 the 0.0005 wins in fact you would round the second one to 2.397 :) but even 2.3961 would be a winner
December 18, 2015

Math (2 Part Question)
12 d = 25 + 8 d 4 d = 25 d = 25/4 = 6 1/4 so if more than 6 days (7 or more) ==================== check how much for 6 days? without = 72 with = 25 + 48 = 73, so no pass how much for 7 days without = 84 with = 25 + 56 = 81, so yes, for 7 days cheaper with pass
December 18, 2015

Math I'm DYING!!!
You are welcome.
December 18, 2015

Hey, careful !
Need parentheses if complex numerator Perhaps you mean (y-5)/3 = 1 multiply both sides by 3 y-5 = 1*3 = 3 add 5 to both sides y -5 + 5 = 3+5 y = 8
December 18, 2015

Math I'm DYING!!!
-21 a + 16 a factor a out a (-21 + 16) a (-5) or -5a
December 18, 2015

Math I'm DYING!!!
1. y - 5/3 =1 you want to get y alone try adding 5/3 to both sides y - 5/3 = 1 +5/3 = +5/3 ---------------- add y -5/3 +5/3 = 1 + 5/3 so y = 1 + 5/3 we need a common denominator, 4 y = 3/3 + 5/3 or y = 8/3 which is 2 2/3 ===========================now check if y = 8/3 then y...
December 18, 2015

sin^-1(4/5)
well I agree with anonymous :)
December 18, 2015

Maths trigonomentry
3 cos x = 5-4 sin x 9 cos^2 x = 25 - 40 sin x + 16 sin^2 x 9 (1 -sin^2x) = 16 sin^2 x -40 sin x + 25 9 - 9 sin^2 x = 16 sin^2 x -40 sin x + 25 0 = 25 sin^2 x - 40 sin x + 16 let z = sin x 25 z^2 - 40 z + 16 = 0 (5 z - 4)(5 z - 4) = 0 wow, that was lucky sin x = 4/5 :)
December 18, 2015

Maths deduce!damon or steve plz help any one
(p-q)^2 = p^2 - 2 pq + q^2 (q-r)^2 = q^2 - 2 qr + r^2 (r-p)^2 = r^2 - 2 rp + p^2 ---------------------------add them 2 p^2 + 2 r^2+ 2 q^2 - 2(pq+qr+rp) = 2[ p^2 + r^2+ q^2 -(pq+qr+rp)] well all those squared quantities are positive so that quantity is > (pq+qr+rp)]
December 18, 2015

not my thing
sorry I suspect you have already tried expanding all that out
December 18, 2015

Social Studies
I said that partly because he established a seaport for Russia opening to the rest of Northern Europe. It was named for him for most of the history since.
December 18, 2015

Social Studies
I have to agree, but would say Navy :)
December 18, 2015

Social Studies
(or at least Magellan's crew )
December 18, 2015

Social Studies
December 18, 2015

exploration or exploitation ?
Circumnavigation is not a technology advance but an accomplishment by Ferdinand Magellan.
December 18, 2015

Math help plz?
if 3x+1 = 4 then x = 1 when x = -3, 3x+1 = -8 I have no idea, sorry
December 18, 2015

Math help plz?
I see, your graph is on a number line
December 18, 2015

do not do magic
I have no idea what your two redlines look like Please give me two points on each line (X1,Y1) , (X2,Y2) or a slope and an intercept or something.
December 18, 2015

ok, here you go
ok x = [ -8+/- sqrt (64-16m) ]/8 so (1/8) * 2 * sqrt (64-16 m) = 3 sqrt (64 - 16 m) = 12 64 - 16 m = 144 16 m = 80 m = 5
December 18, 2015

Huh ?
differs from what by 3 ? do you mean the roots differ by 3 or something?
December 18, 2015

phsice
k x = m g sin 32.5 the frequency has nothing to do with gravity or its direction. The stretching and motion and spring force is all parallel to the slope and the gravitational force component is just constant m g sin theta. omega = sqrt (k/m) as usual
December 18, 2015

history
Since Kofi Annan is an MIT graduate, he is first in line :) However there have been thousands of mediators on thousands of subjects over the years. Recently two Presidents of the US, Bill Clinton and Jimmy Carter have served as mediators getting agreements, albeit temporary, ...
December 18, 2015

Algebra 2
Well, I do not know what the parabola has to do with this. We are asked the distance from (-2,3) to (-1, -9/4) and from that same point (-2,3) to the horizontal line y = -7/4 The second part is trivial -7/4 to 3 is 12/4 + 7/4 = 19/4 we will actually have to do the first ...
December 18, 2015

Physics
.98 kg of water is .98 *10^-3 m^3 of volume mass of zinc = z mass of copper = (4.9-z) volume of zinc = z * 2.5*10^-3 m^3 volume of copper = (4.9-z)* 19.6*10^-3 m^3 so z*2.5*10^-3+(4.9-z)*19.6*10^-3 =.98*10^-3
December 18, 2015

Math
16. Find the final balance in an account with \$660 invested at 3.5% annual simple interest for five years. a) \$23.10 b) \$115.50 c) \$683.10 <------------------- d) \$775.5 ================================== 660 * .035 = 23.10 per year *5 = 115.5 + 660 = 775.50
December 18, 2015

Math
7. 77 is what percent of 192? a) x/100 = 77/192; 4.01% <---------- b) x/100 = 77/192; 40.01% c) x/77 = 100/192; 77.3% d) x/100 = 192/77; 249.4% ================================ 77(100)/192 = 40.01
December 18, 2015

Physics
initial Ke = (1/2) m * 5.4^2 energy lost to friction = 0.1 * m g * 3.50 final ke = initial ke - lost energy (1/2) m v^2 = (1/2) m * 5.4^2 - 0.1 * m g * 3.50 solve for v note that the mass cancels
December 17, 2015

Math
584/421 = 1.387 which is a 38.7 % increase another way 584 - 421 = 163 163/421 = .387 so 38.7% increase Both ways are actually the same but different ways of thinking about it :)
December 17, 2015

Algraba
.07 * 25
December 17, 2015

Physics
How high? Draw it. h = L - L cos 33.6 = L(1-cos33.6) = 3(1-.833) = .501 meters up Potential energy increase = m g h = 25 (9.81) (.501) Ke = (1/2)(25) v^2 = 25(9.81)(.501) cancel the mass and solve for v = sqrt(2 g h) as usual :)
December 17, 2015

Physics!
He is at 10 meters and must jump with an initial velocity up of 5 m/s ow long until he reaches 0 meters (ground) h = Hi + Vi t - 4.9 t^2 0 = 10 + 5 t - 4.9 t^2 or 4.9 t^2 - 5 t - 10 = 0 solve quadratic for time in the air, t in seconds now the truck has to be t seconds away ...
December 17, 2015

english
as well as with
December 17, 2015

Algebra 1
or to say it better there is an infinite number of solutions. For any real x there is a real y on the line.
December 17, 2015

Algebra 1
I guess you mean y - 4 x = 1 and y - 4 x = 1 Those two lines are quite similar, in fact they intersect everywhere and there is no single point where they intersect. This is a trick problem and there is no solution.
December 17, 2015

huh?
Perhaps you copied and pasted here. That does not work on this site.
December 17, 2015

science
1 It is just a turning block.
December 17, 2015

math
if it has to be the same variable on both sides try something like: 7x + 1 = 3x + 5 + 4x -4 in other words 0 x = 0
December 17, 2015

math help plz?
You are welcome.
December 17, 2015

math help plz?
Yes, must grow more than 9 to be more than 70
December 17, 2015

Math
You are welcome.
December 17, 2015

Math
f + f+3 = 19 or 2F + 3 = 19 74 + w -6 = 3 w or 74+w = 3w+6 that means 2w=74-6 = 68 or w = 34 90-5 = 2c 85 = 2c c = 42.5
December 17, 2015

math
16 marbles 1. independent red * blue = 4/16 * 7/16 2. dependent red then blue = 4/16 * 7/15 3.in number two the probability of blue is impacted by the fact that you have taken a marble out. The two draws are not independent on problem 2
December 17, 2015

Math GP typos
Please check what you wrote what is a and what is r in a + a r + a r^2 + a r^3 ......
December 17, 2015

algebra 2
@@@@@@@@__x^2__+3x__-2_______________ x^2 + 1 | x^4 +3x^3-1x^2+5x-3 @@@@@@@@@ x^4 +0x^3+1x^2 @@@@@@@@@-------------------- @@@@@@@@@@@@@@ 3x^3-2x^2+5x-3 @@@@@@@@@@@@@@ 3x^3+0x^2+3x @@@@@@@@@@@@@@ --------------- @@@@@@@@@@@@@@@@@@@ -2x^2+2x-3 @@@@@@@@@@@@@@@@@@@ -2x^2+0x-2...
December 17, 2015

Math dump
First: We can not see the figure so can not help. Second: I see no attempt by you to do the work. I already took the subject and do not need practice. If you are having a specific difficulty, describe your attempt to surmount it.
December 17, 2015

Math
but they each play twice so double it
December 16, 2015

geometry
As far as I know the third side could be anything between 3 feet and 13 feet. 8-5 to 8+5 You need to know more about the triangle.
December 16, 2015