Saturday
September 5, 2015

Posts by Damon


Total # Posts: 21,876

physics
6000 Pascals is 6000 Newtons per square meter. Multiply that by the area of the wall in square meters to get the force in Newtons. The density of water is about 1000 kg /m^3 so the weight of a cubic meter of water is about m g = 1000 * 9.81 = 9810 Newtons so a column of water ...
July 11, 2015

physics
k Q1Q2/d^2 plug and chug
July 11, 2015

physics
Hey, have you bothered to try these yourself?
July 11, 2015

physics
You hear the difference frequency. You want it to be zero. So loosen it more :)
July 11, 2015

physics
find the frequency from the wavelength lambda = c T = c/f then energy = Lank constant * frequency
July 11, 2015

math
8 y = -5 x - 5 1.6 y = -x - 14 slope of first = -5/8 slope of second = -1/1.6 which is -5/8 therefore, no, they have the same slope and are either parallel or identical.
July 11, 2015

Math
2 L + 2 w = 80 or L + w = 40 L w = 300 so w = 300/L so L + 300/L = 40 L^2 - 40 L + 300 = 0 (L-30)(L-10) = 0 try L = 30 and w = 10
July 11, 2015

math
LOL - close enough, a short lunchtime walk.
July 11, 2015

math
MIT, Ocean Engineering. BSc in Physics but went back later for engineering doctorate and taught engineering.
July 11, 2015

math
Anyway, find the total time for the round trip by adding the time out and the time back. Then divide 240 miles by the time in hours
July 11, 2015

math - typo?
Well did he go 60 or 40 on the way back?
July 11, 2015

physics
constant horizontal speed = 22 cos 45 so time to fence = t = 100 /(22 cos 45) so how high is it at time t? h = initial height assume 0 + [ 22 sin 45] t - (1/2)(9.81) t^2 That gives you h in meters. Convert to feet to see if it is higher than five feet.
July 11, 2015

Algebra?
huh ? multiply the side length of a square by four to get the perimeter.
July 11, 2015

Career choice advice needed
I clicked on this only because the title was in Nederlands (of Afrikaans). It would be wise to put the subject in the title so that you get a teacher who knows something about the subject (I really do not, particularly in South Africa)
July 11, 2015

physics
every second a volume of .5 m * .01 m^2 = .005 m^3 comes out of the pipe. 2700 kg/m^3 * .005 m^3/second = 13.5 kg/s
July 10, 2015

algebra
x, x and (x+5) 3 x + 5 = 26 so 3x = 21 x = 7 x = 7 x+5 = 12
July 10, 2015

st joan of arc
tan 48 = height of building/60 tan 56 = height of top of antenna/60 if you want the height of the antenna itself, subtract.
July 10, 2015

Physics
7.9/2 = 3.95 so center of plank is 3.95 from outer end which is 3.95 - 3.5 = .45 inside the edge of the platform so for equilibrium 130 (.45) = 31 x x = 1.89 out from edge
July 9, 2015

Physics
k Q1 Q2 / r^2 note r^2 not r so 1. yes 2 no 3 no 4 yes if you mean 1/r^2 5 not necessarily, Like charges repel.
July 9, 2015

Physics - what ?
equation for what? Did you try to copy and paste something? That will not work here.
July 8, 2015

math (algebra)
r = 1/d r = 1/(2r) r^2 = 1/2 pi r^2 = area = pi/2
July 8, 2015

Calculus
f(x) = |x-2|
July 8, 2015

Calculus
divide top and bottom by x (5 x^2 + x - 1)/3
July 8, 2015

david college
I would not have noticed this if Ms. Sue had not said it was Physics. I never took David College.
July 8, 2015

david college
The charge is the same on each of them. Where else would the electrons on the low side of the top one come from but the high side of the low one :) C = Q/V for each and the voltages add so 100 volts = V1 + V2 100 = Q1/C1 + Q2/C2 but Q2=Q1 = Q so 100 = Q/C1 + Q/C2 = Q (C1+C2)/...
July 8, 2015

Physics
T is tension if the slope of the plane is 32 degrees component of weight down plane = 10 (9.81) sin 32 which is trying to accelerate the mass down the slope so if acceleration up slope is a then T - 98.1 sin 32 = 10 a now the hanging mass force down = mg - T 98.1 - T = 10 a ...
July 8, 2015

No figure
This is kind of challenging without the figure but all you really need is F = m a and weight = mass * local gravity
July 8, 2015

physics
force, direction, distance from A F , up (assumed) , x (unknown) 2500 , down , 0 4000, up , 8 10,000, down , 12.5 3000, up , 21 3500 , down , 25 sum of forces up = 0 so -2500+4000-10000+F+3000-3500 = 0 F -5500 = 0 so F = +5500 up sum of clockwise moment = 0 about A 2500*0 -...
July 8, 2015

maths
so those opposite angles are 130/2 = 65 sum of all the angles is 360 so 130 + 2 theta = 360 theta = 115 so two angles of 65 deg and two angles of 115 degrees
July 8, 2015

maths
90-32
July 8, 2015

Physics (Kinematics Check)
actually I think vi, your initial speed is zero we do not know vf, the final speed. All we know is that it fell 4 m. h = Hi + vi t - (1/2) g t^2 0 = 4 + 0 - (1/2)(9.81) t^2 so t^2 = 4/4.9 t = .9035 seconds to fall 4 meters the average speed is 4 meters/.9035seconds or 4.43 m/s...
July 8, 2015

Calculus
Hmmm, well what you are telling me is that the value of a function at x = a is the same as the limit of the value of the function as x--->a That might usually be true, but what if the function has a different limit depending on which side you approach a from? I am thinking ...
July 7, 2015

Math
2 minutes = 120 seconds (11 words / 8 seconds) 120 seconds = 165 words
July 7, 2015

Math
40 /(2/3) = 120/2 = 60
July 7, 2015

Chemistry-History-ish
Good except the first sentence is misleading. Those experiments did not discover "radioactivity". They were studies into the structure of matter as described in the problem statement. For discovery of radioactivity see "Madame Curie". for example : http://...
July 7, 2015

Math
LOL, draw an equilateral triangle with centroid at origin or a circle with center at origin and radius = 1. for the circle a it just gets to be a bigger circle (so it is similar) b same deal, smaller circle but similar. c try it, I think it will be kind of elliptical (do you ...
July 7, 2015

Chemistry
carbon monoxide This makes the difference clear between carbon monoxide CO and carbon dioxide CO2 You do not need to say mono carbon monoxide or mono carbon dioxide because they are both one carbon and there is no confusion.
July 7, 2015

physics
d omega / dt = alpha = (1400-428)/6.26 = 155 rad/s^2 which is angular acceleration part b theta = 428 t + (1/2)(155)t^2 but t is 6.26 so theta = 5722 radians which is part a
July 7, 2015

Physics
For example Fx = F dot i = |F|cos of angle to x axis
July 7, 2015

Physics
Components of vectors such as components of a force vector are also scalars. They are the dot product of the vector with the unit vector in the component direction.
July 7, 2015

Physics
I am inclined to disagree. Displacement is a vector with magnitude and direction. DISTANCE is the scalar magnitude of displacement. However Work, for example in Joules, is clearly scalar and has no direction. It is a dot product of force and displacement vectors and has no ...
July 7, 2015

Physics
255 cos 60 * 15 assuming that the force is at 60 degrees from the motion. 1912 Joules
July 7, 2015

American History
The colonists made the natives miserable, and they did not even know that the Europeans brought the diseases that killed most of them. See for example http://www.history.com/topics/native-american-history/king-philips-war
July 7, 2015

physics
V entry = a t = 6.3*4.1 = 25.83 m/s v = 25.83 + 6.3 t x = 25.83 t + (1/2)(6.3) t^2 for the second car x = 70.7 t so 70.7 t = 25.83 t + 3.15 t^2 3.15 t^2 - 44.87 t = 0 t (3.15 t -44.87) = 0 so they are at the same x at sthe start of course and at t = 44.87/3.15
July 7, 2015

pysics
Immediately after drop its vertical speed is zero, so no drag. therefore m a = m g and it accelerates down at 32 m/s^2 as it builds up speed and the chute deploys, the air drag increases at about proportional to speed squared until the drag force up equals the m g down and the...
July 7, 2015

math
You are welcome.
July 7, 2015

math
on your graph mark the point where x = 1 and y = -3 from there go right one and down one (slope of -1) and mark a second point. draw a line through those two points.
July 7, 2015

math
y = m x + b put in slope m y = -1 x + b put in point y = -2 where x = 1 -3 = -1(1) + b so b = -2 so y = -x -2
July 7, 2015

Chemistry
mass * ( heat of fusion + heat capacity * 100 + heat of vaporization)
July 7, 2015

physics
mg downward 30 N upward net downward = m g - 30 g is not in Newtons but in m/s^2. It is more like 9.81 m/s^2 on earth but ok, use 10 m/s^2 net downward = 5 kg ( 10 m/s^2) - 30 = 50 - 30 = 20 Newtons
July 7, 2015

statistics
Sure looks like .7 to me. The ones not in the window have nothing to do with your problem.
July 7, 2015

science
although it also has rotational energy Kinetic spin energy = (1/2)I omega ^2 = (1/2)(2/5) (.2)(R^2) omega^2 but v = R omega so add (1/2) (2/5)(.2) (25)
July 7, 2015

science
(1/2) m v^2 = .5*.2*25 Joules
July 7, 2015

physics
west inertia before = west inertia after 2000 * 20 = 5000 * Vwest south inertia before = south inertia after 3000 * 20 = 5000 * Vsouth V = sqrt (Veast^2+Vsouth^2) tangent of angle west of south = Vwest/Vsouth compass course = 180 + that angle
July 7, 2015

Math
.2*2 + .3*1 -.3*2 -.2*0 .4 + .3 -.6 - 0 .1 I agree
July 5, 2015

American history
............I have already intimated to you the danger of parties in the State, with particular reference to the founding of them on geographical discriminations. Let me now take a more comprehensive view, and warn you in the most solemn manner against the baneful effects of ...
July 5, 2015

Calculus
dy/dx = slope = 2*5 x - 4 + 0 The 12 has no effect on the slope The slope is a straight line with y intercept of -4 and slope of 10 The 5 is half the slope of the derivative
July 5, 2015

math
5,747 * 1.021^n = 36,000,000 1.021^n = 36,000,000/5,747 = n = log (36,000,000 / 5,747)/log 1.021 = 421 ============================ check 1.021^421 = 6307 6307*5,747,000 = 3.6*10^10 = 3.6*10,000,000,000 =36,000,000,000 sure enough
July 5, 2015

science
weight * tan 4 = m a m g tan 4 = m a a = g tan 4
July 5, 2015

maths
LOL, should have checked that !
July 5, 2015

maths
We know that (x-sqrt 2) is a factor 6 x^3 + 2 x^2 - 10 x -4 sqrt 2 = 0 (x-sqrt 2)( a x^2 + b x + c) = 0 well, c better be 4 (x-sqrt 2)(a x^2 + b x + 4) = 0 now I will use distributive property to split this up x (a x^2 + b x + 4) -sqrt 2 (a x^2 + b x + 4) = 0 x terms: 4 x - b ...
July 5, 2015

Math
The first roll has no effect what so ever on the results of the second roll. They are independent events. Dependent events are those where the first outcome has an effect on the second. For example if you have two green balls and two red balls in a hat. The probability of ...
July 5, 2015

physics
There is no such thing as a force of 2 kg, sorry
July 5, 2015

Math
x^2 = t^2 cos^2 y^2 = t^2 sin^2 x^2 + y^2 = t^2(cos^2+sin^2) = t^2 but t^2 = z^2 so x^2+y^2 = z^2
July 5, 2015

math
36 + .2(450-100) assuming one day
July 4, 2015

physics
oh max acceleration magnitude = A w^2 = 5.6*10^-7 * (5040)^2
July 4, 2015

physics
harmonic motion with w = 2 pi *frequency or 2 pi/period y = A sin w t dy/dt = v = A w cos w t d^2y/dt^2 = a = -A w^2 sin wt = -w^2 y here v max = Aw = 2.82*10^-3 and A = 5.6*10^-7 so w = 2 pi f = 2 pi/T = 2.82/5.6 * 10^4 = .504*10^4 = 5040 radians/s f = 5040/2pi = 801 Hz T = 1...
July 4, 2015

physics
You are welcome.
July 4, 2015

physics
F = k x k = 82/.0191 F = (82/.0191) * .0520
July 4, 2015

phys
(I wonder if whoever gave you this problem really thought out the implications of the landing :)
July 4, 2015

phys
h = Hi + Vi t - 4.9 t^2 assume the road was level so Vi = 0 1.5 = 20.2 + 0 - 4.9 t^2 4.9 t^2 = 18.7 t = 1.95 seconds in the air to fall 18.7 meters so how far did he go horizontal in those 1.95 seconds? d = u t 60 = u * 1.95 u = 30.7 meters/second horizontal for the whole jump...
July 4, 2015

science 207 lab wk 5
How on earth would we know what is in wk 5 of science 207? We are not at your school or perhaps even in your country.
July 4, 2015

Science
4.9 t^2
July 4, 2015

Science Help Not sure
Ui = initial speed = 126*10^3/3600 = 35 m/s 65-126 = -61*10^3 meters / 3600 seconds = -16.94 m/s speed change -16.94/8 = -2.12 m/s^2 acceleration d = Ui t - (1/2) a t^2 = 35*8 -(1/2)(2.12)(64) = 212 m so A
July 4, 2015

Science
v = a t hey, try some of these yourself !
July 4, 2015

Physics
Vi up = 15 sin 30 = 7.5 m/s initially u = 15 cos 30 = 13 m/s forever Hi = 40 then h = Hi + Vi t - 4.9 t^2 0 = 40 + 7.5 t - 4.9 t^2 or 4.9 t^2 - 7.5 t - 40 = 0 t = [ 7.5 +/- sqrt(56.25 + 784) ] / 9.8 use + root of course t = 3.72 seconds then v = Vi - 9.8 t = 7.5-36.5 = -29 m/s...
July 4, 2015

physics
3 sin thete = 2 theta = 41.81 V across = 3 cos theta = 2.24 mi/hr (1/4)/2.24 = .112 hr = 6.7 minutes He has zero velocity parallel to the shore (that is the whole point) However he has speed of 2.24 mi/hr perpendicular to the shore.
July 4, 2015

Physics
well, I suppose they both have the same acceleration, call it a The total mass is 5000 kg The total force on the system is 6000 N so a = 6000/5000 = (6/5) m/s^2 Now how much of that is on the truck? F = 3000 a = 3000 (6/5) = 3600 Newtons from the car on the truck so the force ...
July 3, 2015

physics
All yo can really find in this world is DIFFERENCES in potential energy. In this case, whoever wrote the question probably expected you to define zero potential at the FLOOR so the h you use for part 1 which is 6.5 -2.5 = 4 is NOT the h you use for part 2 for part 2, use the ...
July 3, 2015

physics
LOL, it takes time, it is almost midnight, and I have to work tomorrow.
July 2, 2015

physics
v = omega r 1. 6.12 * 2.20 = 13.464 m/s 2. 6.12 * 15.2 = 93.024 3. 6.12 * 3.15 = 19.278 (1/2) m v^2 1. .5 * 6.36 * 13.464^2 = 577 Joules 2. you can do the next two 3. add them I = m r^2 1. 6.36 (2.2)^2 = 30.8 2. you can do 3. you can do add them for total I Ke = (1/2) I omega^...
July 2, 2015

physics
There are only two horizontal forces in this problem, at the wall and at the ground. Therefore they are equal and opposite, call the magnitude F now balance vertical forces 886 + 350 = force down = 1236 N that is therefore the normal force up at the ladder base the max ...
July 2, 2015

math
4 = 2^2 so (2^2)^(x+2) = 2^x but (a^b)^c = a^(bc) so 2^(2x+4) = 2^x 2x+4 = x x = -4
July 2, 2015

math
Now you can solve what I gave you for x which is the pounds of nuts with cashews.
July 2, 2015

math
5 t^2 - 7 t - 1 = 0 t = [ 7 +/- sqrt(49+20) ]/ 10 t = [ 7 +/- sqrt(69) ] / 10
July 2, 2015

math
3.95 x + 1.15 = 1.70 3.95 x = .55 x = .139 yes then .5 - x = .361 ------------------ check 6.25 * .139 = .869 2.30 * .361 = .830 ------------------- add ****** .5 lbs = 1.699 or in other words 1.70
July 2, 2015

math
x with cashews costs 6.25 x (.5-x) with peanuts costs 2.30 (.5-x) so 6.25 x + 2.30(.5-x) = 1.70
July 2, 2015

Math
if she works 40 hours per week (we are just guessing that), then she worked 80 hours for $383 383/80 = $4.7875 per hour
July 2, 2015

Math
The y intercept is where the line hits the y axis, in other words when x = 0 that means that in the equation of the line y = m x + b the y intercept is where x = 0 and y = b saying a point is on -3 and the other on + 5 does not help me You have to say for example at one point ...
July 2, 2015

Finite
maximize p = 8x + 10y subject to .6x + .45y <= 400 .4x + .55y <= 300 =============================== Vertex Lines Through Vertex Value of Objective (566.666667,133.333333) .6x+.45y = 400; .4x+.55y = 300 5866.666667 Maximum (666.666667,0) .6x+.45y = 400; y = 0 5333.333333...
July 2, 2015

Finite
http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html
July 2, 2015

Finite
cc = .6 x + .45 y </= 400 rb = .4 x + .55 y </= 300 income = i = 8 x + 10 y objective, maximize graph those functions, check the corners
July 2, 2015

Finite Math
well, in that first column I would like to see 1 0 0 so I would multiply row 1 by 2 subtract the result from row two and put that result where row 2 is then I would multiply row 1 by 3 instead of by 2 and subtract the result from row three, placing the result in row three.
July 2, 2015

Applied Mathematics ( Mechanices
a ) m g b ) m(g+5) c ) m(g-5) on earth g is about 9.81 m/s^2
July 2, 2015

physics
the braking force is opposite to the direction of motion, so we are doing negative work on the train delta W is negative Are we putting heat into the train? I think not. In fact heat is going out into the air as the brakes heat up. delta Q is negative So I suspect that the ...
July 2, 2015

mathematics
0.400 * 6.00 = $2.40
July 2, 2015

Physics
a = dv/dt = 4 i + 14 t F = m a 40 = 4.6 sqrt (4^2 + 14^2 t^2) (40/4.6)^2 = 16 + 196 t^2 solve for t use that t to get v and a Then v dot a = |v||a| cos theta
July 2, 2015

Physics
tension T force F horizontal vertical: T cos 32.9 = m g horizontal: T sin 32.9 = F
July 2, 2015

algebra
or ln (2-x) = 14 e^{ln(2-x) = 2-x so 2-x = e^14 x = 2 - e^14 x = - 1202602
July 1, 2015

Differential Equation
hmmm, not sure but dy/dx = [(1-y^2)/(1-x^2) ]^.5 dy/(1-y^2)^.5 = dx/(1-x^2)^.5 let y = sin p let x = sin r dy = cos p dp and dx = cos r dr cos p dp/cos p = cos r dr/cos r dp = dr
July 1, 2015

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