# Posts by Damon

Total # Posts: 31,628

Physic
potential energy U = (1/2) k x^2 (1/2)(3200 N/m)(.035)^2 max speed = Vmax (1/2) m Vmax^2 = U compression of weak spring, same potential energy when stopped U = (1/2)(1600)(x^2) x is in meters of course

Physics Prob.
U = m g h = m g 2(1-cos 45) (1/2) m v^2 = U The tension is PERPENDICULAR to the motion, does ZERO work. Why did you ask !!! ???

Physics
(1/2) m v^2 = m g h (1/2) m v^2 = m g h + (1/2)m(2.3^2) exactly the same. These trick questions should not be getting to you. If you need to think about it if he jumps up at 2.35 he will pass the end of the board at 2.35 on the way down.

CHEMISTRY
The point is that the H2O2 lasts for a long time if kept on a shelf in its original bottle (which by the way is dark to keep photons from encouraging decomposition). The effect of temperature is minor if in the range from room temp to body temp. However if you pour it on your ...

physics
distance north = N = 300 cos30+400 cos 60 distance east = E = -300 sin 30+400 sin 60 magnitude of displacement = sqrt(N^2+E^2) angle east of north =tan^-1(E/N)

English
https://quizlet.com/1857072/arthurian-legends-questions-for-exam-flash-cards/

precalc
cos can be -1 or + 1 if cos = -1 y = 2 + 8 = 10 if cos = +1 y = -2 + 8 = 6 or just sketch a graph

Math helppp
in hundred millions A + 3 = T + H A + T + 6 = 4 H A + T + H = 59 so 3 - T - 6 = T - 3 H 6 - H = 4 H -59 5 H = 65 H = 13 - T - 3 = T -3(13) 36 = 2 T T = 18 A + 3 = 13 + 18 A = 28 so A 2, 800, 000, 000 H 1, 300, 000, 000 T 1, 800, 000, 000

physics
Vertical problem: (1/2) m V^2 = m g h V = sqrt (2 g h) at bottom V =sqrt(2*9.81*180.6 time at ground: average v = V/2 so t = 180.6/v = time at ground Horizontal problem (use t from above) a = 13.0/2.63 u = a t d = (1/2) a t^2 speed = sqrt(u^2+V^2)

Math
same same

physics
The period is proportional to Radius^(3/2) so Tx/Ty= (4R)^3/2 / R^3/2 = 2^3 = 8 times 8 * 90 = 360*2 = 720deg ============================== why Radius^(3/2) mv^2/R = G m M/R^2 so if k^2 = GM v = k R^-.5 T = 2 pi R/v = 2 pi R/kR^-.5 = constant*R^1.5

calc error
a = F/m = 16.6/3.1 d = (1/2) a t^2 3.8 = (8.3/3.1) t^2 t = 1.19 seconds v = a t = (16.6/3.1)(1.19) = 6.38 m/s or do using change in Ke = work done (1/2) 3.1 v^2 = 16.6*3.8 v = 6.38 m/s

physics
a = F/m = 16.6/3.1 d = (1/2) a t^2 3.8 = (8.3/3.1) t^2 t = 2.01 seconds v = a t = (16.6/3.1)(2.01)

Physics
You are welcome.

Physics
https://www.jiskha.com/display.cgi?id=1511047418#1511047418.1511048268

Physics
did it the first time

Physics
meters

Physics
half a wavelength in the pipe. wavelength = velocity of sound times period so 1/2 wavelength = pipe length = (1/2)(340 m/s or whatever)/300 It has nothing to do with the diameter

Physics
Assume the light gets there immediately (c = 3*10^8 m/s) speed of sound in air = about 343.4 m/s at 20 C 10 seconds * 343.4 m/s = 3434 meters = 3.434 km or 2.13 miles By the way, those of us who do navigation at sea approximate the time to hear a sound after seeing the cause (...

Physics
There are no external forces on the boat/man system. Therefore if it was at rest there is no acceleration and the center of mass does not move. If the man moves away from shore in the boat, the boat moves toward the shore to keep the center of mass stationary.

Physics
v = Vi - 10 t h = Hi + Vi t - 5 t^2 Hi = 0 initial height t = 6 so t rising = 3 (symmetry of parabola) v = 0 at top so Vi = 10 *t at top = 30 m/s h = 0 + 30(3) - 5 (9) = 90 - 45 = 45 meters (good throw)

sign error in last line
9 x + 7 y = -20

Algebra 1
when x = 4, y = -8 when x = -3 , y = 1 so as y goes up 9 from -8 to +1 x goes down 7 from 4 to -3 so slope = 9/-7 = -9/7 so it is of form y = (-9/7) x + b to find b, use one of those points when x = -3, y = 1 is easy 1 = (-9/7) (-3) + b 1 = 27/7 + b b = 7/7 -27/7 = -20/7 so in...

Mathhhhhh helpppp plz
Which equation has (2,-1) as a solution? y=2x-1*** y=x+3 y=x-3 y=-2x+1 ======================= Now look It has to work when x = 2 and y = -1 Try the first one y=2x-1 so -1 = 2*2 - 1 so -1 = 4-1 -1 = 3 ******* NO WAY __________________________' The second one y = x + 3 so -...

Chemistry
Ca = 40 g/mol N = 14 g/mol 3 Ca = 120 g/mol of Ca3N2 2 N = 28 g/mol of Ca3N2 so we need 28 g N for every 120 g of Ca so yes, if you have 50 g of each, then Ca is the limiting reagent I only need 50 *28/120 = 21 grams of N so 50 -21 = 29 would be left over Ca3N2 molar mass = ...

Mathhhhh helpppp
if (2,6) is right then 6 = 2 -4 but it is not so try a -5 = -1 -4 -5 = -5 that seems to work

history
It is not in Wikipedia because there was no compromise about the attack on Pearl Harbor, like period.

Math Ms.Sue help plzz!!
union is all of them 1,2,3,5,7,10 are in A and C intersection of A and C is the one that is in both, namely 2 Please Google Venn diagram. B is 2 through 8 even 2,4,6,8 D is 1 through 9 odd 1,3,5,7,9

PHysics
You are welcome. Now you have two ways to do it, both valid.

PHysics
acceleration = change in velocity/change in time magnitude of change in velocity = 100 m/s (all in one direction) time = distance/average speed = 0.9/50 = 1.8/100 = .018 so a = 100/.018 then F = m a = .050*100/.018 = 278 m/s^2 which is about 28 times gravity

Science
When in danger or in doubt, pick the one you never heard of :) http://sciencenetlinks.com/student-teacher-sheets/integumentary-system/

Slope Intercept
slope = (1- -3) / (3-1) = 4/2 so y = 2 x + b now put in 1 for x and -3 for y to get b

maths
(6+6+6+1)/3 = 2+2+2 + 1/3

Pre Calculus
sin 2x = 2 sin x cos x x is in quadrant 3 so cos x is negative sin 2x = 2(-0.6) cos x but cos^2 x = 1 - sin^2 x cos^2x = 1 - .36 = .64 = 64 * 10^-2 so cos x = + or - 8*10^-1 = -0.8 because we know it is - so sin 2x = 2 (-0.6)(-0.8) = + 0.96

Science
Hint One of those is a noble gas, something to do with Superman.

Math
You are welcome.

Math
I already told you c was right

Math
6/10 = 3/5 *3/3 = 9/15 yes

Math
3/15 = 12/60 no 8/24 = 1/6 = 12/72 no 5/18 = 25/90, good Now you do #2

math
In other words your calculator won the argument this time :)

math
NO -x^2 is the same as -1 * x^2 =-1 * 10,000 = -10,000

You try
They are all the same. I will do the middle one. (18/30) = 3/5 if you divide top and bottom by 6 what other one is 3/5? 20/35 = 4/7 50/90 = 5/9 36/48 = 3/4 60/100 = 6/10 = 3/5 whew, finally

math
(2/3)/6 multiply top and bottom by 3 2/18 = 1/9

physics
I think you are really asking how long does it take to go up 0.88 meters and how long to come back down. This is presumably on earth where the acceleration due to gravity is -9.81 m/s^2 So what was initial velocity component upward? (1/2)m Vi^2 = m g h conservation of energy ...

ah, not allowed
We are here to help students, not to provide answers.

math
use half that area, hemisphere

PreCalculus
If I use Steve's link but with base ten log I get x = .633895 or 1000

Physics
now why is max range at 45 degrees? https://www.wired.com/2010/09/maximum-range-in-projectile-motion/

Physics
maximum range is at 45 degrees launch from horizontal if there is not air friction. (1/2) m V^2 = m g h so V = sqrt (2 g h) that is your launch speed u = V cos 45, horizontal speed,constant Vi = V sin 45 = initial vertical speed range = u t where ti is time in air need to get ...

Hellpppp calculus
multiply the first equation by 2 .2 x + .6 y = 3.0 .2 x + .6 y = -1.2 Two parallel lines, they never intersect. There is no solution.

Math helppp
320 is 40 degrees west of north north speed= +225 cos 40 east speed = -225 sin 40 70 is 70 degrees east of north north speed= 190 cos 70 east speed = 190 sin 70 difference in north speed =225cos40-190 sin70 =-6.18 km/h difference in east speed =-225sin40-190sin 70 =-323.17 km/...

huh?
If they are all at the top they are at the same elevation? This must be at some intermediate time which you have not given.

Pre-Algebra
yes

Pre-Algebra
200 (1.08)^3

Physics
horizontal F = 131 cos 37 = m a = 33.7 a so a = (131/33.7)cos 37

Science
if you double the volume by adding water the mols of acid per liter is half. It is no longer .5 M but is .25 M

Science
I am inclined to agree with dog.

physics
find the circumference C = pi D = pi * 0.65 meters per revolution C * n = 3,000 meters so n = 3,000/C

Physics
initial vertical velocity = Vi=40 sin 30 = 20 m/s (not m/s^2) constant horizontal velocity = 40 cos 30 How long to get there? 40.8 m/(40 cos 30) = 1.18 seconds so now the vertical problem, how high after 1.18 s h = Vi t - (1/2) g t^2 h = 20(1.18) -4.9(1.18)^2 all yours :)

Physics
C = Q/V V = (1/C) integral i dt dV/dt = (1/C) i but i = -V/R so dV/dt = (1/C) -V/R or dV/V = (-1/RC) dt (I bet you knew that) so ln V = (-1/RC) t V = Vi e^(-t/RC) (which you also know) and Q = CV = CVi e^(-t/RC) at t = 8.2 Q(8.2) = Cv = .4 CVi = CVi e^(-8.2/RC) so .4 = e^(8.2...

scince
Combustion is not a property but a chemical reaction.

Chemistry
a and d are crazy. c is not true because water has a efined volume for its mass and temp we are left with b

Science
one way is by density measure what it weighs in air. measure the volume of water it displacees if sunk. mass =weight/g (of course if you use scale that is not needed} density = mass/volume lot of other ways, color, hardness .....

physics
Good grief ! The NET force is zero.

physics
Oh come on, the velocity is constant therefore net force = 0

I did one for you. Now you try.

physics
assume you mean 5.50 * 10^6 Joules 6.50 hr * 3600 s/hr = time in seconds power = Joules / time in seconds ( which is Watts ) part B: power * time = 1850 * 9.81 * 1.20

physics
change in momentum = 0.060 kg * 30 m/s time = 0.005 seconds force = change in momentum/ time

physics
normal force = 450*9.81 = 4414. N friction force = 4415 mu so 380 + 380 = 4415 mu

Physics
A) .44 * 17 * 9.81 = 17 a solve for a B) .21 * 17 * 9.81 = 17 a (less once you get it moving)

Math
well 20 = 2*2*5 16 = 2*2*2*2 If there are others I do not know of them there are others with three like' 12 = 2*2*3 18 = 3*3*2 8 =2*2*2

Spanish
Could you think maybe it had something to do with Fidel Castro in Cuba?

math
well, do what they said y = x - 6 but they said y = -x so -x = x-6 6 = 2 x x = 3 in the next one y = (x-8) use that in the second equation

Math/calculus
The velocity is perpendicular to the radius. It is tangent to the circle which is 2 pi R around.

Math/calculus
R = 1.50* 10^8 km circumference= 2 pi*1.50*10^8 = 9.42*10^8 km T =365.2564 * 24 = 8766 hours = 8.766*10^3 so v = C/T = (9.42/8.766)10^5 = 1.075*10^5 = 107,500 km/hr

Science
I think b eg NaCl, ionic bond Na gives electron to Cl and d, covalent bond https://chem.libretexts.org/Core/Organic_Chemistry/Fundamentals/Ionic_and_Covalent_Bonds

algebra
You are welcome.

algebra
no ones like number 13 Find the x- and y- intercepts of the graphs passing through the given points. 13. (4, -2) and (5, -4) we need the equation of the line through those points what is the slope m? m = (-4 - -2)/(5-4) = -2/1 = -2 so y = -2 x + b what is b? to find it put a ...

algebra
well, look at number 4 for example the average rate is the total change in f divided by the change in x at end = 2*3 - 1 = 5 at begin = 2*0-1 = -1 so change in f= 5 -(-1) = 6 and change in x = 3-0 = 3 so av rate = 6/3 = 2

you try first
These are cookbook problems and I see no effort by you to follow the recipes so I have no idea why you are having trouble with them.

Physics
Fh = force up of hands at x = xh from axle Fa = force up from wheel axle at x = 0 Wb = 67 at xb from axle Wc = 511 at xc from axle then Fa+Fh = 67+511 Fh * xh = 67 * xb + 511 * xc

Math/calculus
330 clockwise from North is 360 - 30 = 30 degrees west of north That is 90+30 = 120 in math talk counterclockwise from the x axis. However being a navigator and not a mathematician I will stick with 30 degrees west of north:) How far did it go? 125 *1.5 hours = 187.5 km west...

Math
distributive property .8(2.5+4.95+6) can be distributed to .8*2.5 +.8(4.95)+ .8(6)

200*1.08^3

physics
mass = 0.047 kg weight = 0.047 * 9.81 = 0.461 Newtons lever arm = 0.16 meter toque = 0.461 * 0.16 Nm

Math (Area formed by 3D coordinates)
sketch graph first :) A to B = +2i-3j-1k B to D = +1i+5j+1k D to C = -2i+3j+1k parallel to AB C to A = -1i-5j-1k parallel to BD so use AB cross BD for example

Math
if (ax-2) is your denominator then if ax = 2, you are dividing by zero if a = 1 then if x = 2 ax = 2 x =2/a and the denominator ax-2 = 0 boom!

Physics 1
weight = m g = 1400 * 9.81 friction force = .5 * 1400 * 9.81 = 6867 N a = F/m = 6867/1400 = -4.9 (half a g of course) v = 34 - 4.9 t v = 0 at stop so t = 6.94 seconds d = 34 t - (1/2)(4.9) t^2 = 34(6.94) - 2.45*6.94^2 = 236 - 118 = 118 meters

physics
NONE, there is no motion in the direction of the string tension. It continues at the same speed forever.

physics
F = m a -8000 = 1000 a a = -8 m/s^2 v = 40 - 8 t we want v = 0 8 t = 40 t = 5 seconds to stop (yikes!) d = 40*5 - (1/2)(8)(25) = 200 - 100 = 100 meters for part b how long to for 45 m? 45 = 40 t -4 t^2 solve quadratic for t then v = 40 - 8 t

Math
If you got that linear equation by regression analysis on the data above then yes and it does make sense as far as we know from the data.

To live in fear and hide [FOR???] because

necessary for providing a safety = necessary as a safety measure.... risk of homelessness suicide. ==== then new sentence === living in poverty : living in poverty, becoming victims and trying to.....

History
http://www.encyclopedia.com/history/news-wires-white-papers-and-books/slavery-issue-election-1848 It made slavery THE issue.

eNGLISH
Although it is perfectly clear, the last phrase beginning "A bill..." is not a sentence. Perhaps say " My bill will fully recognize, include .... " .

Algebra 2
first an ellipse formula is (x-h)^2/a^2 + (y-k)^2/b^2 = 1 so this is NOT an ellipse If that + were a - it would be a hyperbola So This is a hyperbola.

Physics
http://hyperphysics.phy-astr.gsu.edu/hbase/molecule/vibrot.html

Physics
2 pi f = sqrt(k/m) for m you can use that reduced mass or just use the mass of a hydrogen atom which is about 1 gram/mol or .001 kg /6*10^23 atoms = (1/6)*10^-26 = 1.66 *10^-27 kg because the H is the part that moves because the Cl is 35.5 times as massive which is what that &...