# Posts by Damon

Total # Posts: 29,637

**word problem**

L = 4w+9 if L = 85 w = 76/4 = 19 if L = 49 w = 40/4 = 10 10</= w </= 19

*February 26, 2017*

**physics**

The mass has nothing to do with this problem since acceleration is not asked for F = k (2q)q/.1^2

*February 26, 2017*

**physics**

work = force * distance = q E d = change in potential energy = qV 48 = .1 V

*February 26, 2017*

**physics**

forces on q1 attractive k =10^-12* usual k to account for ? force in direction of Fq3=k(8)/.4^2 force in direction of Fq2=k(6)/.4^2 force perpendicular to opposite side Fy= Fq3 cos 30 + Fq2 cos 30 force parallel to opposite side Fx= Fq3 cos 60 - Fq2 cos 60 F = sqrt(Fx^2+Fy^2) ...

*February 26, 2017*

**math**

Does he pay at the beginning of the year or the end?

*February 26, 2017*

**Math**

y = k x 6 = 3 k k = 2 y = 2 x 2/3 = 2 x x = 2/6 = 1/3 ================= 25 = m (1.25) so m = 25/1.25 a = F/m = 35 /(25/1.25) = 1.25 * (35/25)=1.75 You could have written that down immediately by proportions but: 1. I am a physicist 2. You are doing algebra of direct variation.

*February 26, 2017*

**Chemistry**

2 * 6.49 * Avogadro's number which is about 6.02*10^23

*February 26, 2017*

**Math**

I can get it in powers of cos but not first power sin^8 = sin^2 * sin^2 *sin^2 *sin^2 but sin^2 = 1 - cos^2 sin^2*sin^2 = 1-2cos^2+cos^4 (1-2cos^2+cos^4)^2 = 1-4cos^2x+6cos^4x-4cos^6x+cos^8x

*February 26, 2017*

**Sorry, misread it**

assumed x with 3

*February 26, 2017*

**Pam**

If you do not do calculus you complete the square x^2 - 3 = y x^2 - 3 + (3/2)^2 = y + 9/4 (x-3/2)^2 = y+9/4 vertex at (3/2 , -9/4)

*February 26, 2017*

**Math**

6.848*10^9 people .22*57.9 *10^6 miles^2 so [ 6.848/(.22*57.9) ]10^3 =.5376 * 10^3 = 538

*February 26, 2017*

**Pam**

( 1,000,000 , 1,000,003 )

*February 26, 2017*

**Pam**

LOL - looks like = x to me, the 3 is tiny Perhaps she means where the slope is zero? dy/dx = [(x+8)(2x+11) -x^2-11x-16)]/bottom^2 where is numerator = 0? 0 =2x^2+27x+88-x^2-11x-16 0 = x^2 + 16 x + 72 complex roots :( none

*February 26, 2017*

**mATH..OHHHH NOOOOO PLEZ HELP I AM STRUGGLING**

In this link which MsSue gave you will find: http://www.mathsisfun.com/quadrilaterals.html That a square is also a rectangle and a rhombus.

*February 26, 2017*

**if a square, then a rhombus**

a square has 4 equal sides, so does a rhombus however a square has 90 degree corners a rhombus could have 90 degree corners, but not necessarily. therefore If a square, then a rhombus If a rhombus, maybe a square In other words, a square is a special case of a rhombus

*February 26, 2017*

**mATH..OHHHH NOOOOO PLEZ HELP I AM STRUGGLING**

Try to draw a square that is not a rhombus

*February 26, 2017*

**word problem, please help**

41 = 25 + 4 t 16 = 4 t t = 4 so t>/= 4

*February 26, 2017*

**physics**

Vi = 180,000 meters/3600 seconds average speed during deacceleration= Vi/2 distance = (Vi/2)* 20 = 10 Vi

*February 26, 2017*

**Algebra**

a (x-2)(x-3) = 0 a[ x^2 -5x + 6 ] = 0 f(x) = a[ x^2 -5x + 6 ] when x = 1 f(1) = 12 = a[ 1-5+6] 12 = 2 a a = 6 so f(x) = 6x^2 -30 x + 36

*February 26, 2017*

**math**

prob jeff not = 1/4 prob Justin will = 2/5 the two events are independent so (1/4)(2/5) = 1/10

*February 26, 2017*

**math**

letters a through z. There are 26 on my keyboard order matters so permutations of 26 taken 4 at a time = 26!/[22!]= 26*25*24*23 10 numbers (0 through 9) again order matters = 10!/8! = 10*9 so in the end 10*9*26*25*24*23

*February 26, 2017*

**Algebra**

new salary = x = 1s + .093 s so x = 1.093 s

*February 26, 2017*

**?hours?**

proofread how many hours?

*February 26, 2017*

**Science**

Normal force is indeed 810 mass = normal force /g = 810/9.81 = 82.57 kg but it depends what your class uses for g. I use 9.81 but some classes even use 10m/s^2 (I guess they live on a slightly more massive planet :)

*February 26, 2017*

**Math**

3x >/= -6 x>/= -2

*February 26, 2017*

**Math**

You are welcome.

*February 26, 2017*

**Math**

6 > 10 z - z^2 well if z = 0, the right hand side is 0 and 6 is > 0 so A works by the way, the others do not work ;)

*February 26, 2017*

**Science**

If the speed is constant and the cable is horizontal then the friction force equals the tension, 60 N The normal force is m g = 15.0 * 9.81

*February 26, 2017*

**Science**

Hard to say since I have no idea where point A is.

*February 26, 2017*

**Social Studies**

Then I would indeed pick A. However B was also true of many Germans and played a part in the rise of Adolph Hitler.

*February 26, 2017*

**Social Studies**

2. I think A AND B

*February 26, 2017*

**Social Studies**

1. NOT C, yes to the others

*February 26, 2017*

**Algebra**

x along river and y 600 = x + 2y so x = 600-2y A = x y A = (600-2y)y = 600y - 2y^2 I assume you do not know calculus so complete square to find vertex of parabola. y^2-300 y = -A/2 y^2 -300 y+(300/2)^2 = -A/2 + 150^2 (y-150)^2 = -(1/2) (A-45,000) vertex at y = 150 and A = 45,...

*February 26, 2017*

**College Algebra**

.05x +.06(10,000-x) = 550 .05 x + 600 -.06 x = 550 50 = .01 x x = 5000

*February 25, 2017*

**Need mass**

say m normal force m g Friction force = .5 mg so T - .5mg = m a T = m (1 + .5g) = 5.9 m

*February 25, 2017*

**Math**

first one wrong (1/3)base area*height second one wrong, same formula third one wrong, same formula again I have no idea what the bottom 2 are about.

*February 25, 2017*

**Math**

the volume of anything pointy with straight sides = (1/3) base area * height

*February 25, 2017*

**science**

Well, we will run out of fossil fuel first of all. It is by definition not "long term" because we are using it up faster than plants are turning into coal and oil and even gas. However there are more immediate obvious problems such as air pollution and land pollution...

*February 25, 2017*

**Physics help please**

If it is exactly the same distance from each speaker then there is no difference in path length between the two paths and the signals superimpose to give a maximum.

*February 25, 2017*

**do not do magic**

we do not see your figure or line of reflection.

*February 25, 2017*

**PHYSICS**

m a = 520*2 = 1040 N third law ---> -1040 N net force on car = car mass * car a = 1400 * 2 = 2800 N the tires exert 1040 N more on the road to accelerate the trailer, but that is not what you asked :)

*February 25, 2017*

**math**

try common factor 2 182/3 60 2/3

*February 25, 2017*

**PHYSICS**

If it moves with constant V the forces add to zero. to counter first Fx = -6.2 N to counter second Fy = +5 N |F| =sqrt(5^2 + 6.2^2 ) = 7.96 N quadrant II tan T = 5/-6.2 T = 180 - 38.9

*February 25, 2017*

**MAthematicas**

slope of x = 1 is anything/0 which is UNDEFINED

*February 25, 2017*

**Algebra 2**

easy way g = [(x-3)/2 ] ??? g(1) = [(1-3)/2 ] = -1 f(-1) = 1-3+6 = 4 --------- hard way f(g)=[(x-3)/2]^2+3[(x-3)/2 ]+6 put in x = 1 f(g)=[(1-3)/2]^2+3[(1-3)/2 ]+6 = 1 -3 +6 = 4

*February 25, 2017*

**Algebra I**

zero when x = 1, always + elsewhere 2 x^4 would be symmetric about y axis HOWEVER the -8x adds a sloping line to that which destroys that symmetry so not symmetric about any of them

*February 25, 2017*

**Math**

Why could he not be 877.375 meters high? Integer means 877 or 878

*February 25, 2017*

**MATH**

x = 3 has no y axis intersection. It is a vertical line through x = 3, no solution , no relation , no way :)

*February 25, 2017*

**Geometry**

I assume D is on AB? Is it an altitude hitting AB at 90deg ? if so A is 60 and B is 30 then CD = 8 sqrt 3 AC = 16 AB = 32 BC = 16 sqrt 3 so perimeter = 48 + 16sqrt3

*February 25, 2017*

**Algebra**

80 a +200 b = 160 *20 = 3200 and a + b = 20 so b=20-a 80 a + 200(20-a) = 3200 80 a + 4000 -200 a = 3200 120 a = 800 12 a = 80 a = 6 2/3 pounds so b = 20-a = 13 1/3 pounds

*February 25, 2017*

**math**

no, not distributive property of multiplication If the question were (5x+3)(8x+1) no plus sign, so TIMES then you could say 5x (8x+1) + 3 (8x+1) That would be distributive property.

*February 25, 2017*

**math**

You do not show any multiplications or divisions in your given problems. All you can do is collect like terms. (5x+3)+(8x+1) is the same as 5x+3+8x+1 which is 13 x + 4 =========================== similarly (2t^2-3t)-(7t^2-5t) = 2 t^2 - 3 t - 7 t^2 + 5 t Note that +5 t due to ...

*February 25, 2017*

**Algebra 2**

you do not have either + or - 3.57 people

*February 25, 2017*

**Math**

A. y = -2x/3 + 4 B. goes through (0,-2) and (3,0) (0+2)/(3-0) = 2/3 = (y+2)/(x-0) y+2 = 2x/3 2x -3y = 6 C. y = -3 x + b 2 = -3(1) = b b = 5 y = -3x + 5

*February 25, 2017*

**Trig identies, Calculus**

use x^2-y^2 = (x+y)(x-y) c^4-s^4 = (c^2+s^2)(c^2-s^2) = 1 (c^2-s^2) = c 2x

*February 25, 2017*

**matrix, linear transformations**

first h*g 4 12 0 6 then k * h*g 0 6 4 12 in detail h * g |1 2| | 4 0 | |4 12| |0 1| | 0 6 | |0 6 | then |0 1| |4 12| |0 6 | |1 0| |0 6 | |4 12|

*February 25, 2017*

**Calculus**

I agree because as x increases the integral decreases.

*February 24, 2017*

**you mean 3/4 I assume**

cos is - in quad two sin^2 T + cos^2 T = 1 9/16 + cos^2 T = 16/16 cos^2 T = 7/16 cos T = -sqrt 7/ 4 agree with you

*February 23, 2017*

**Math**

but what is 28/4 !!!! ???? LOL

*February 23, 2017*

**Chemistry**

do the silver one first Ag 108 g/mol Cl 35.5 g/mol AgCl = 143.5 g/mol so 5.57 g AgCl has (108/143.5)5.57 = 4.19 g of Ag so 8.12 g stuff has 4.19 g Ag so 4.72 g stuff has 2.44 g Ag so we have 4.72-2.44 = 2.28 g of C and H we got 7.95 g of CO2 C = 12 g/mol O2 = 32 g/mol CO2 = 44...

*February 23, 2017*

**Precal**

Actually I just used the trig identity tan = sin/cos same difference :)

*February 23, 2017*

**Precal**

sqrt(5) / 2

*February 23, 2017*

**Chemistry**

Oh, that Einstein guy again? how much energy in a photon of wavelength 902 nanometers ? approx 900*10^-9 = 9*10^-7 meter L f = c 9*10^-7 f = 3*10^8 f= (1/3) * 10^15 E = h f E = 6.6*10^-34 * (1/3)*10^15 E = 2.2 *10^-19 Nope not quite strong enough to spring an electron free.

*February 23, 2017*

**chemistry help, urgent!**

Google buffer

*February 23, 2017*

**Math**

B. does it have constant slope? (-1+5)/(0+2) = 4/2 = 2 ((1+1)/(1-0) = 2/1 = 2 (3-1)/(2-1) = 2/1 = 2 :) slope, m = 2) C. y = mx + b so y = 2x-1 D. y = 2(10)-1 = 19

*February 23, 2017*

**physics**

m * v = 8.0 m * 10 = 8.0 m = 0.8 kg (about a pound)

*February 23, 2017*

** NO**

4. It would be correct if you typed it correctly 5.1 * 10^-8 Your answer is nonsense. the ^ symbol means "to the power" or superscript 5. Nonsense again 10^12 (Please learn to type exponents) is smaller than ANYTHING * 10^13 or 14 or 21 or whatever bigger than 12 ...

*February 23, 2017*

**math**

1. -10 * -1 = 10 2. doubles to * 2 at 4 doubles to * 4 at 8 doubles to * 8 at 12 8*90 = 720 3. No because not a power of ten. Your answer is wrong 4.8 IS between one and ten 1007 is NOT a power of ten. Perhaps 10^7 ????

*February 23, 2017*

**Math**

Sketch a graph ! I notice a dip for example.

*February 23, 2017*

**Math**

multiply everything by 2 -6 + n = 18 so? add 6 to both sides

*February 23, 2017*

**Engineering Science N4**

at the point where it has acceleration = a and velocity = 0, I assume the static friction rules. normal force = m g - F sin 15 friction force = .4(mg-F sin 15) pull force horizontal = F cos 15 so Fcos15 -.4(mg-F sin 15)= m a

*February 23, 2017*

**math help asap**

Oh come on 15/10 = ? 24/16 = ? 30/20 = ?

*February 22, 2017*

**Educational Technology**

I am using library, school and other computers around town being very busy with local political issues. I google in to answer a question once in a while but usually do not remember to write my name in above.

*February 22, 2017*

**Hey, we did the one with the copies**

Your turn.

*February 21, 2017*

**Algebra**

machine 1 does n copies/170 min so n/170 copies/min machine 2 does n/119 copies/min so n = (n/170 + n/119) t 1/t = 1/170+1/119 = .014286 so t = 70 min

*February 21, 2017*

**math**

0 = -32 t + 28 so t = 28/32 google projectile motion in English units (acceleration of gravity = -32 ft/second^2)

*February 21, 2017*

**Math**

LOL, anywhere else !

*February 21, 2017*

**Algebra**

n and n+32 1/n + 5/(n+32) = 1/6 multiply all terms by 6n(n+32) 6(n+32) + 5(6n) = n(n+32) 6n + 192 + 30 n = n^2 + 32 n n^2 - 4n - 192 = 0 (n-16)(n+12) = 0 n = 16 n+32 = 48 ================ ================ check 1/16 + 5/48 = 1/6 ??? 3/48 + 5/48 8/48 1/6 sure enough

*February 21, 2017*

**math**

ratio is 1/2 so one of these: 8 4 6 3 4 2 2 1 difference is 2 so 42

*February 20, 2017*

**physics**

365.25*24 = h, number of hours distance = 2 pi r = 6.28* 1.5*10^8 km speed = distance/hours

*February 20, 2017*

**suggestion**

Maybe point (a,b,c) line like z = m x + n y + k find vector along line find vector from point to random spot on line do cross product, show independent of spot chosen on line. That cross product is perpendicular to the plane containing the two lines

*February 20, 2017*

**geomatry**

You are welcome :)

*February 20, 2017*

**Neil**

not area, perimeter

*February 20, 2017*

**geomatry**

sides a, b c perimeter = a+b+c perimeter 4 a + 4 b + 4 c =4(a+b+c)

*February 20, 2017*

**no way**

You say rectangle. I assume typo? Did you read what you wrote? All terms in the area are - ? -17.5 x^2 -138 x - 27 = 231? +17.5 x +138 x + 258 = 0 x = -3.05 or x = -4.84

*February 20, 2017*

**College Algebra**

f = 3(6x-5)^2 -4 = 3 (36 x^2 -60 x +25) - 4 = 108 x^2 -180 x +71

*February 20, 2017*

**Physics**

How much Ke should she have at 328 m? m g h = 71(9.81)(1370-328) Joules How much Ke does she actually have? (1/2) m v^2 = (1/2)(71)(68)^2 The difference is how much work is done by air friction. ========================== At 328 meters she has a total energy of m g 328 + (1/2...

*February 20, 2017*

**value**

log x^n = n log x a 2a 3a 4a .......

*February 20, 2017*

**Physics**

1/d^2

*February 17, 2017*

**algebra**

e^[2(3x^2-2)]

*February 16, 2017*

**Math**

small = s and b = big s = b-2 1/s + 2/b = 5/12 so 1/(b-2) + 2/b = 5/12 agreed multiply by 12 b (b-2) 12 b + 24(b-2) = 5 b(b-2) 12 b + 24 b - 48 = 5 b^2 - 10 b 0 = 5 b^2 - 46 b + 48 0 = (b-8)(5b-6) so use b = 8 s = b-2 = 6

*February 16, 2017*

**Physics**

normal force = m g max static = .75 m g so m a = .75 m g for slide to start or a = .75 g now the slide a = .75 g v = a t 33 = .75 g t t = 33/(.75*9.81)

*February 16, 2017*

**physics**

m g h = m g (3.4/2)

*February 16, 2017*

**Physics - Calculating work required**

This is a problem about POTENTIAL! The path does not matter ! That is the whole point. The voltage potential difference is the difference in potential energy of a unit charge at the two voltages. work done = charge * change in V

*February 16, 2017*

**Physics**

force = 55*9.81 Newtons pressure = force/area if area is in meters^2 then force is in Pascals

*February 15, 2017*

**physics**

Vi = 110,000 meters / 3600 seconds v = Vi + a t at end, v = 0 so 0 = Vi -49 t t = Vi/49 then d = Vi t + (1/2) a t^2 d = Vi (Vi/49) - (1/2)(49)(VI^2/49^2) d = (1/2)Vi^2/49

*February 15, 2017*

**Algebra**

I worked it out in the way you are probably used to. Scroll down

*February 15, 2017*

**Algebra**

44+47 = ? mi/h time = 69/speed

*February 15, 2017*

**Math**

divide by 1,000 kg/tonne

*February 15, 2017*

**arrgh upside down**

.3456/.84 = .4114

*February 15, 2017*