# Posts by Damon

Total # Posts: 29,637

**Physics**

http://en.wikipedia.org/wiki/Interference_(wave_propagation) note: [2A] cos (kx- wt) cos(phase angle/2)

*March 8, 2017*

**math**

By up I suppose you mean up in y because you have no z coordinate. Just increase all the y locations by 3 and leave the x coordinates the same. eg: S(4,4)

*March 8, 2017*

**no idea**

do not see picture

*March 8, 2017*

**physics**

Spaceship 2 has it all:) 300*0 = 0 300*4 = 1,200 kg m/s

*March 8, 2017*

**physics, vectors**

If a unit vector in the x or east direction is i, the y direction or north is j, and the z direction or up is k, then: momentum vector=12,000 i + 0 j + 0 k magnitude = sqrt (12,000^2+0^2+0^2) =12,000 kg m/s

*March 8, 2017*

**Physics**

200(1.5) = .5 w w = 600 Newtons

*March 8, 2017*

**incomplete**

What is the question? a = (13.4-0)/5 m/s^2 = r*alpha v = 0 + a t = r*omega d = 0 + 0t + (1/2)(5)t^2

*March 7, 2017*

**Hot math questions**

LOL :)

*March 7, 2017*

**English**

well, "he" is a person :) Had got no business to be there After the day was done — "It's very rude of him," she said, "To come and spoil the fun." So who does she think the night belongs to?

*March 7, 2017*

**Algebra math 150**

height times average of a and b

*March 7, 2017*

**Physics**

The increase in gravitational potential energy = m g h where h is the HEIGHT change, the increase in distance from the center of the earth. Work = distance times force IN THE DIRECTION OF MOTION 200 * 4 = 800 Joules alternatively force component up slope * 4/sin 20 = 200 sin ...

*March 7, 2017*

**math 1**

when you typed 1/3x + 4 I assume you mean (1/3)x + 4 and not 1/(3x) + 4 or 1/(3x+4) y = (8-x) so (8-x) = (1/3) x + 4 24 - 3 x = x + 12 4 x = 12 x = 3

*March 6, 2017*

**Math**

a = 3 m b = 8 m c = 6b = 48 m a/c = 3 m/ 48 m = 1/16

*March 6, 2017*

**Chemistry**

(a) but when she opens the bottle the air inside is still at 1 atm so must escape out the open top--> whoosh !

*March 6, 2017*

**math 73**

.22 c + .02 m = .04(20) c + m = 20 so m = (20-c) so .22 c +.02(20-c) = .8

*March 6, 2017*

**Physics**

omega is angular velocity in radians/second omega R = 5 m/s so omega = 5/.3 = 16.7 radians/second Ke = (1/2)I omega^2

*March 6, 2017*

**Math**

You are welcome.

*March 6, 2017*

**Math**

Make a number line on a piece of paper. Draw the situation on it. Left 8 from -20 -20-8 = -28

*March 6, 2017*

**you need limits**

infinite as stated

*March 6, 2017*

**Calculus**

assuming that your answer is correct dy/dx = x^2 e^(x^3/3) but e^(x^3/3) = y-2 so dy/dx = x^2 (y-2) hummm I'll try dy/(y-1) = x^2 dx ln(y-1)= x^3/3 + c (y-1) = e^[x^3/3 + c] y-1 = e^(x^3/3) e^c y-1 = Ce^(x^3/3) y = 1 + Ce^(x^3/3) 3 = 1 + C C = 2 so y = 1 + 2e^(x^3/3)

*March 6, 2017*

**Science**

1. wrong 2. right 3. wrong 4. both mass and distance G M1M2/d^2 5. both (or they would bash each other) 6. right 7. It is near the poles that you have darkness at noon when the sun is above the other Capricorn or Cancer :) 8.Right 9. WRONG!!!! (google moon landing) 10. Wrong...

*March 6, 2017*

**English**

Nope. None of them are.

*March 6, 2017*

**Social studies**

Nope, remember that 3/5 of a person thing?

*March 6, 2017*

**Math**

(1/4) 16 = 4 lettuce (1/8) 16 = 2 punpkin (1/2) 16 = 8 red tulips 4+2+8 = 14 16-14 = 2 rows of carrots

*March 5, 2017*

**math**

recursive means you get the value from an earlier value or values. An+1 = An + 5 for example Explicit means you calculate it without reference to the former value A = 5 n for example

*March 5, 2017*

**Math**

x = 4 y = -2 what more can I say?

*March 5, 2017*

**Science**

meters (not kilograms or seconds)

*March 5, 2017*

**Calculus**

Nah, I carried an incorrect extra x

*March 5, 2017*

**Calculus**

10 x-3xdy/dx-y(3x)=6y^2 dy/dx (6y^2+3x)dy/dx = 10 x -3xy dy/dx = (10x-3xy)/(6y^2+3x)

*March 5, 2017*

**social studies**

I am trying to calm down and go back to the calculus question.

*March 5, 2017*

**social studies**

http://www.abrahamlincolnonline.org/lincoln/speeches/gettysburg.htm

*March 5, 2017*

**social studies**

For heaven's sake Google ! READ THE ADDRESS @!

*March 5, 2017*

**Maths**

3 * 7 = 21

*March 5, 2017*

**physics**

(1/2) m v^2 = m g h so v = sqrt (2 g h) g = 9.81 m/s^2 h = 30 m

*March 5, 2017*

**value**

m g h/t

*March 5, 2017*

**Physics**

well first the 2 ohm resistor Vtwo = i R = 1.2*2 = 2.4 volts Now the two in parallel They are both at voltage V V = i1 (6) = i2 (18) but we know i1+i2 = 1.2 so i1 = 1.2 - i2 6(1.2- i2)=18 i2 7.2 = 24 i2 i2 = 7.2/24 = .3 amps through 18 ohm i1 = 1.2 - .3 = 0.9 amps through 6 ...

*March 5, 2017*

**History**

North American white pine for spars.

*March 4, 2017*

**History**

Archimedes screw pump, capstan, windlass, aft rudder on pintles with wheel, deadeyes and lanyards .....

*March 4, 2017*

**History**

LOL, could go on for hours. steam boxes for plank bending. oakum, pitch pine, eventually copper bottom paint

*March 4, 2017*

**History**

white oak frames and planking and locust trunnels (tree nails)

*March 4, 2017*

**History**

eat limes "Lime-juicers" avoid scurvy

*March 4, 2017*

**History**

Navigation technology (determination of longitude)

*March 4, 2017*

**Math**

divide by density, not number of people (50/750)100 = 6.67 %

*March 4, 2017*

**physics**

1.05*10^5 * .12*.18 = ---- kilograms now it is not clear if that is one of four tires if so then multiply by 4 I wonder because around 2,000 kg is reasonable for a car and four times that is pretty heavy.

*March 4, 2017*

**Science**

Venus is volcanic so I suppose you would call hardened lava rocky.

*March 2, 2017*

**Math Trig**

d1^2 = 225-100 = 125 d2^2 = 225 - 64 distance between = d1+d2 add because the walls are in front of and in back of the fireman:)

*March 2, 2017*

**Science**

Now wait a minute, what do you think dew point means? It is the point where there is so much water in the air that the air can not hold any more at that temperature. That means the relative humidity is 100%

*March 2, 2017*

**math**

A bag contains 2 white marbles amd 3 green marbles. Two marbles are drawn at random, one after the other. The first marble is replaced before the second one is drawn. What is the probability that the first marble is green and second one is white?

*March 2, 2017*

**Health**

Now you are getting beyond my knowledge of the subject but I think you are correct. The other answers do not make sense.

*March 1, 2017*

**Health**

You are welcome.

*March 1, 2017*

**Health**

I agree with your answers

*March 1, 2017*

**Math**

L = w + 8 (L-5 )(w+4) = L w (w+8-5)(w+4) = (w+8)w (w+3)(w+4) = w^2 + 8 w w^2 + 7 w + 12 = w^2 + 8 w w = 12 etc

*March 1, 2017*

**Math**

x + y = 60 .4 x + .9 y = .75 (60)

*March 1, 2017*

**Math**

4 1/4 - 3/4 the easy way is 3 5/4 - 3/4 = 3 2/4 = 3 1/2 however if your were into making live hard for yourself you could 4 1/4 - 3/4 = 4-2/4 = 4 -1/2 = 3 1/2

*March 1, 2017*

**Math**

well because it is awkward to subtract 3/4 from 1/4 You could do it and work with the negative fraction but it is easier to say: 4 1/4 = 3 5/4 then it is easy

*March 1, 2017*

**Math**

You sure need a big calculator but I would settle for 3.14159 (88.3773)^2 because I do not remember pi any further than that.

*March 1, 2017*

**math**

Your teacher asks tricky questions :)

*March 1, 2017*

**math**

6 * 4 = 24 so 24 dollars for every bag of 7 apples 120/24 = 5 bags of 7 apples you got one free in each bag, so 5 free 5*7 = 35 apples total friend bought 21/7 = 3 bags for $24 each. 3 * 24 = 72 dollars $4 for an apple is ridiculous

*March 1, 2017*

**TEAS 6 MOMETRIX**

alternative to that which is called "elimination" is "substitution" from the second equation x + y = 5.90/2 = 2.95 so you can say x = 2.95-y now use that in the first equation 4(2.95-y) + 3 y = 9.55 11.80 - 4y + 3 y = 9.55 y = 11.80 -9.55 = 2.25 again

*March 1, 2017*

**TEAS 6 MOMETRIX**

4 x + 3 y = 9.55 now multiply your second equation by 2 4 x + 4 y = 11.80 subtract the first equation from the second 0 x + 1 y = 11.80-9.55 = 2.25 the end

*March 1, 2017*

**Huh**

I have no idea what your problem looks like. LS 154 means something to you somewhere, not to me on Massachusetts Bay.

*March 1, 2017*

**math**

I got 14 13 + 10 + 9 + 9 = 41 41 - 27 = 14 25/2 = 13 17/2 = 9 for two seaters

*March 1, 2017*

**math**

No fair, can not cut two person desk in half :) Please check my reply below.

*March 1, 2017*

**math**

then subtract the 27 you have and buy 14

*March 1, 2017*

**math**

13 + 10 + 9 + 9 needed

*March 1, 2017*

**math**

No, 25/2 is not a two person desk need 13 desks for 25 people and 9 desks for 17 people TRICK QUESTION :)

*March 1, 2017*

**math**

Unless you cut them in half of course :)

*March 1, 2017*

**math**

well for 25 you need 12 1/2 but that is not possible so 13 +10 + 9 + 9 ----- 41 but we have 27 so we need 41 - 27 = 14

*March 1, 2017*

**math**

40% of 30% of 5,000 .4*.3*5,000 .12*5,000 .1*5,000 + .02*5,000 500 + 100 600

*March 1, 2017*

**history**

Think Walt Whitman, what was he about?

*March 1, 2017*

**Equations with Fractions**

You are welcome.

*March 1, 2017*

**Math**

http//www.mathsisfun.com/geometry/pythagorean-theorem-proof.html

*March 1, 2017*

**Math**

Need to draw it but can not, going to look for drawing. Here it is :) The square with the triangles outside. http//www.mathsisfun.com/geometry/pythagorean-theorem-proof.html

*March 1, 2017*

**Math**

x^2 + y^2 = 61 x x^2 y^2 1 1 == 60 nope 2 4 == 57 nope 3 9 == 52 nope 4 16 = 45 nope 5 25 = 36 SCORE!!! 5 and 6 6 36 well then 25 of course 7 49 = 12 nope 8 too big

*March 1, 2017*

**Physics**

the rope is evidently mass less. total force up = total force down because nothing is accelerating. Total force down = m g Tension in rope is T on each side of mass horizontal component of T = T cos angle above horizontal right and left vertical component of T = T sin angle, ...

*February 28, 2017*

**Social Studies**

yes

*February 28, 2017*

**Math**

agree and by the way: 726 = 2*363 ok but 2*363 = 2 * 3 * 121 BUT 121 = 11*11 :) so we have 1*3*11*11 =11^2 * 6 so sqrt(11^2 * 6) = 11 sqrt 6

*February 28, 2017*

**Math**

726 = 2*363 ok but 2*363 = 2 * 3 * 121 BUT 121 = 11*11 :) so we have 1*3*11*11 =11^2 * 6 so sqrt(11^2 * 6) = 11 sqrt 6

*February 28, 2017*

**Physics**

do this with north (y) and east (x) components the same way as the one you asked below.

*February 28, 2017*

**Physics**

y component = North = 3 + 5 sin 45 x component = East = 5 cos 45 d = sqrt (x^2 + y^2) tan T = y/x where T is angle above x axis 90-T = angle clockwise from north

*February 28, 2017*

**algebra**

a(n+1) = a(n) - 8 a = -15 arithmetic sequence see http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html a = -15 a(n) = -15 -8(n-1)= -15+8 -8n = -7 -8n I agree C

*February 28, 2017*

**physics typo?**

power in Watts = work in Joules per unit time = m g h /t = 81.5 * 9.81 * 2.70 / 15.50 Watts By the way I do not believe it took the student 15.5 seconds to lift the weight. Do you have a typo?

*February 28, 2017*

**World History**

Horses? Firearms? The fact that many of the natives were oppressed subjects of more powerful tribes and were willing to join the Spanish in overthrowing their masters? Relative immunity to common European diseases that wiped out whole tribes of natives?. Sorry, I see a lot of ...

*February 28, 2017*

**Social Studies**

I am not familiar with the subject but suspect from the context that one is from Ontario and the other from Quebec :)

*February 27, 2017*

**Physics**

assuming that E is horizontal tan 20 = q E / m g

*February 27, 2017*

**Algebra**

1 straight line, no bends 2 parabola, bends once 3 cubic , bends twice etc n bends n-1 times :)

*February 27, 2017*

**Social Studies**

Hummm, what else is new?

*February 27, 2017*

**still wrong**

x^2[4y^3dy/dx] +y^4[2x]+3dy/dx -12x^2 = -5sin x [4x^2y^3+3]dy/dx = 12x^2 -2xy^4-5sinx dy/dx =(12x^2 -2xy^4-5sinx)/[4x^2y^3+3]

*February 27, 2017*

**left out 3y term**

x^2[4y^3dy/dx] +y^4[2x]+3 -12x^2 = -5sin x 4x^2y^3 dy/dx = 12x^2 -2xy^4-5sinx -3 dy/dx=3/y^3-y/2x-(3+5sinx)/(4x^2y^3)

*February 27, 2017*

**calculus**

d/dx of x^2y^4+3y-4x^3=5cos x-1 ((( note - dx/dx = 1))) so x^2[4y^3dy/dx] +y^4[2x]-12x^2 = -5sin x 4x^2y^3 dy/dx = 12x^2 -2xy^4-5sinx dy/dx=3/y^3 - y/2x- 5sinx/(4x^2y^3)

*February 27, 2017*

**Math Need Help!!**

yes sky, right, 144 = 12^2 = 2^4*3^2 an whole number to an even power is a perfect square. Unfortunately 2^5 = 32 and 5 is NOT an even number.

*February 27, 2017*

**Math**

R = 4 D R+16 = 2(D+16) 4 D + 16 = 2D + 32 2 D = 16 D = 8

*February 27, 2017*

**MATH**

A/B = 2/3 B/C = 3/4 A/B / B/C = 2/3*4/3 = 8/9 C/A = 2 (8/9)/2 = 4/9

*February 27, 2017*

**path around is 2 m wide?**

Assuming that, please proofread what you post r = 25 R = 25+2 = 27 so pi(27^2-25^2)

*February 27, 2017*

**Math**

for example: http://www.mathsisfun.com/square-root.html

*February 27, 2017*

**physics**

For a resistor V = R i for an inductance L where w = 2 pi f V = L di/dt if i = sin wt for example then di/dt = w cos wt and V = (L w) i The L w is called reactance , sort of like "resistance" the ratio of voltage to current

*February 27, 2017*

**Algebra**

Given: f(x) = 8-4x A. Find f(-2) f(-2) = 8-4(-2) = 8+8 = 16 ============================ B. Find x, when f(x) = 8 8-4x = 8 so -4x = 0 x = 0/-4 x = 0 =========================== I can not very well graph for you. It is a straight line y = -4 x + 8 when x = 0, y = 8 when y = 0 x...

*February 26, 2017*

**Is E horizontal?**

tan 30 = q E / m g

*February 26, 2017*

**ph**

q E = 1.6*10^-19 * 800 Newtons

*February 26, 2017*