Saturday
June 25, 2016

Posts by bobpursley

Total # Posts: 41,322

Chemistry
termperature.
June 24, 2016

physics
an atom is placed.....such that its plane normal to the electron orbit makes.... What electron< Orbit of what? Is some one really thinking electrons orbit a central nucleus of an atom? Somehow, I am missing the point of all this.
June 24, 2016

math
Let x be the number of student who belongs to both groups; y, belongs to the band only; z, belongs to the orchestra only. Then x+y=48---------(1) x+z=36---------(2) y+z=12---------(3) (2)-(3)=> x-y=24----------(4) (1)+(4)=> 2x=72=> x=36
June 24, 2016

Physics
http://www.zo.utexas.edu/courses/Thoc/Thermodynamics.html
June 24, 2016

Physics
Energy: evolution leads to processes that satisfy the second law of thermodynamics.
June 24, 2016

Math year 10
a. k-s=5 or s=k-5 b. ks=s(k-5)
June 24, 2016

Math
let the number be 1abcdef f=e+d f=1+b a=c a=f a+b+c+d+e+f+1=45 ok you have five equations and six unknowns. There can be no single solution. so take the last equation, and start substituting a + (b+1) + c+ (d+e) + f=45 f+f+f+f+f=45 f=9, a=9, c=9,b=8, or 1989de9 is the number ...
June 24, 2016

maths
B=.75L 100=sqrt(B^2+L^2) 100=L sqrt(.75^2+1) 100=L sqsrt(9/16+16/16)=L sqrt(25/16) 100=L*5/4 L=80 B=3/4 * 80=60 area=BL
June 24, 2016

geometry
I recommend you get a tutor, or a study buddy. You do no know how to read math symbols, and as a result are making us guess what you are reading.
June 24, 2016

geometry
There has to be something more to this.
June 24, 2016

math
28*8=14*L L=16meters
June 24, 2016

math
3/2 N -5/6 N=4/3 get a common denominator of 30 3*15 N -25N=40 20N=40 N=2
June 24, 2016

Pre-Cal: Word Problem
I dont agree the sine and inverse sine functions are one to one. The sine function is cyclic. arcsin(1/2)=30 deg and 150 and ...
June 23, 2016

Chemistry PLS HELP
the molecules in random motion cause diffusion into the air, and the NO2 goes into the air. other answers: A) TRUE, BUT HAS NOTING TO DO WITH WHAT IS HAPPENING. B) NOT TRUE, THEY HAVE SAME NUMBER OF MOLECULES AT SAME TEMP/PRESSURE, BUT EACH MOLECULE (n2 VS NO2) HAS DIFFERENT ...
June 23, 2016

Physics
No, no, no. Forces are vectors, you have to add them as vectors. You have the across the diagonal force (distance is not 1), and the two corner forces at 90 degrees to each other. If you analyse it you can eliminate all side directions, so (In my head) the force will be along ...
June 23, 2016

math
20 percent
June 23, 2016

physics
What is y? x is distance. Where is acceleration here?
June 23, 2016

physics
100kg m /sec= mass*velocity=50kg*V V= 2m/s
June 23, 2016

General Physics
2. An Earth satellite moves in a circular orbit 687 km above the Earth's surface. The period of the motion is 98.3 min. (a) What is the speed of the satellite? (b) What is the magnitude of the centripetal acceleration of the satellite? (a) Using formula of T=2πr/v I ...
June 23, 2016

General Physics
b) I'm applying the definition of average velocity into vectors, thus finding a displacement vector in the time interval and plugging in. Then I use the the standard formulas for magnitude and theta. 1) Δr=(BC)-(AB)=(-980km)j-(-410km)i=(-410km)i+(-980km)j.***correct 2...
June 23, 2016

Chemistry
let M be moles of X2O3 so in M moles of X2O3, you have 2 M of X2, and 3 M of O so if mass X in 2M is .36, and mass O in 3M is .20, then M=(.2/3)/18=.2/54=1/270 moles but also M=.18/atomicwtX or atomicwtX=.18*270=48.6
June 23, 2016

Chemistry
15 carat*1gram/5carats=3 grams. moles bentoite=3grams/molmassbentiote mol mass is= 1Ba+1Ti + 3SI+9O3 look up the atomic mass of each of those... mol mass= 137 + look these up and add them. Calculate the moles of bentoite. now for moles Si, multiply by three
June 23, 2016

Biology
what do organisms need? energy source; material to build molecules How do they secure it? Many different ways: from heat, or sunlight, or chemical (food) attribute of life? ability to reproduce, grow.
June 23, 2016

engineering science
and, of course, the question is?
June 23, 2016

engineering science
work done: force*distance speed trolley: 39m/40sec power= work done/40sec
June 23, 2016

Physics
10N
June 22, 2016

English
All acceptable, however, number 4 is probably the best, with number 2 and 6 being the least best.
June 22, 2016

History
The French bitterly resented the losses of the French Indian Wars, and wanted to keep Britian from becoming powerful.
June 22, 2016

Science
I am wondering what .02 molecules looks like, and how were they counted?
June 22, 2016

science
the momnetum of the elephant is much more because of math. Now if the cheetah is hungry, and has sharp teeth, it could be a little difficult to
June 21, 2016

CALC
sarah, I am not certain what you meant to type. i get this dy/dx= -4x * e^ what is the exponent of e?
June 21, 2016

Physics
Isn't this a standard formula? C=k*episilon*Area/separation C=Q/V set them equal, solve for k
June 21, 2016

Chemistry
do the calculation, verify 3.6 I did it in my head
June 21, 2016

Math/Conversions
how much left= 1/3 (orig amount) how much drank: orig amount-1/3 origamount=2/3 orig amount
June 21, 2016

Math/Conversions
33 4/5 * 2/3= 33*2/3 + 2/3*4/5 = 22 8/15=22.53333
June 21, 2016

Math (pre-celc 12)
lets look at an example. A four q test, 3 t, 1 f tttf fttt tftt ttft 4!/1! * 4!/3!=4*3*2*4 Nope.. What about 4!/3!1! lets try that then with a five q, 3T, 2F tttff ttftf tfttf ftttf fttft ftftt ffttt tfftt ttfft tftft 5!/3!2!=5*2=10 And ten it is.
June 21, 2016

Control systems: LaPlace Xforms
thanks
June 21, 2016

science
Sodium Phosphate has highest bp highest fp is glucose, and high osmotic pressure is dependent on number of ions, sodium phosphate
June 21, 2016

english i just need someone to simplify this sente
I can't simplify your sentence because I have no idea what your point is. The sentences make NO SENSE.
June 21, 2016

Algabra
If I were going to any for profit "school", I can't imagine trying to get thru by copying any of the other students work. My guess usually all will fail with the same answers. The last woman I remember who called herself pretty was in the Movie Snow White, with ...
June 21, 2016

physics
I would do it this way find acceleration, and initial velocity. distance covered in the fifth second is distance in the first five seconds minus distance in the first four... d(5th)=vi(5-4)+a/2 (25-16)=vi+4.5a 76=vi+4.5a now, the 10th second 116=vi(10-9)+a/2(100-81) or 116=vi...
June 21, 2016

VICTORVILLE COMUNITY
what is 385milrd/17.5 hours ?
June 20, 2016

Physics
I am wondering from what height it was hit by the player.
June 20, 2016

science
F= m*a
June 20, 2016

science
a=F/m=40N/2kg=2Om/s^2
June 20, 2016

math
180600miles/7hours= 2.58E4 mi/hr
June 20, 2016

Physics
frictionaless? yes, conserved. PE is converted to KE.
June 20, 2016

physics
d=1/2 a t^2=1/2 *10*25 m
June 20, 2016

physics 2
gauge pressure=g*1E3kg/m^3*14m = 9.8*1E3*14 Pa=9.8*14kPa absolute pressure, add 101kPa to the above to add in atmospheric pressure.
June 20, 2016

algebra
and...?
June 20, 2016

Physical Science
frequency*wavelength=speed wavelength=speed/frequency. 1030 is above the speed of sound in air.
June 19, 2016

Chem
do the math, but by insptection, I bet it is 4.
June 19, 2016

Physics
total energy at balloon = launch energy mgh+ 1/2 m (12.2)^2=1/2 m vlaunch^2 solve for vlaunch
June 19, 2016

Physical Science Please Check Answers?
I checked them. You got 1 and 8 right. On 7 the question makes no sense to me. You missed the rest.
June 19, 2016

PHYSICS EXAM PRACTICE QUESTION
Net force=mass*acceleration 2300E-600E=900*a solve for acceleration a. vf=a*t d=1/2 a t^2 Work=force*distance=2300*d KEcar=1/2 m vf^2 Friction=600*d rate power loss=friction work/8
June 19, 2016

Physics
NO. V=IR, so I=V/R=8/60 amps
June 19, 2016

physics
hf=hi+vi*t-4.8t^2 0=20+0*t-4.8t^2 solve for t. vf=vi+9.8t, using t from above, solve for vf
June 19, 2016

algebra
3n+n^2=10 n^2+3n-10=0 (N-2)(n+5)=0 n= 2, or -5
June 19, 2016

Physics
g=10m/s^2 ????? Nowhere on the Earth is it that high, why would a teacher tell you to use that? Why not 14m/s^2? time in air: 20m=5m/s *t t=4sec hf=hi+vvertical*t-4.9t^2 0=hi+0*4 -4.9(4^2) hi= ??
June 19, 2016

physics
.001m=.8m*25E-6*(tf-20) solve for tf
June 19, 2016

science
I doubt if the bullet has the same mass as the pistol. Something is wrong. Mb*Vb=Mp*Vp
June 19, 2016

chemistry
Hydrocarbon+O2>>> CO2 + H2O CO2+Ca(OH)2>>CaCO3 + H2O mass CaCo3=10g MassC=10/molmassCaCO3*atomicmassC = 10/100*12=1.2 g of C=.1mol Mass water=2.25 moles H = 2.25/18 * 2=.25 lowest ratio C:.1 H:.25 or CH.25 or CH4 is the empirical formula.
June 19, 2016

Fideon
change km/hr to m/s (multiply by 1000/3600) Momentumchange=mass*(changeainvelocity) = mass*(90-16)(1000/3600) m/s^2
June 19, 2016

math
if sin theta=1/3, then sin^2+cos^2=1 cosTheta=sqrt(1-sin^2)=sqrt(8/8) = 2sqrt2 /3 and ctnTheta=cos/sin= 2sqrt2 then 2 ctn^2+2= ..... 18?
June 19, 2016

Math
it is increased by one thousand.
June 19, 2016

math
nothing following, but it is about 49 in my head.
June 19, 2016

physic
momentum is conserved; .15*3.8=4.75*V V= you do it.
June 18, 2016

Math Probability (Coin Flip)
I don't see an easy way to do this, as there are 50 different numbers of heads. Pr(1)=(.5)^1(.5)^49 and the Q(r) the second person is the same, so the joint probability that both will get only one H is Pr(1,1)=(.5)^2(.5)^98 =(.5)^100 Now, Pr(2,2)=(.5)^4(.5)^96=.5^100 and ...
June 18, 2016

MATH
length=(60/360)*2PI*radius
June 18, 2016

Math
Hmmmm. 30cc. The question is what concentration do you wish?
June 18, 2016

Algebra
a. imaginary roots x=+-sqrt(-n)=+ i sqrtn b. then a double root at zero.
June 18, 2016

geometry
My screen shows no shaded area.
June 18, 2016

Physics
and the question is?
June 18, 2016

Physics
hf=hi+v*sinTheta*time-1/2 g t^2 hf=hi=0 you know Theta, v (9.35m/s), solve for t 0=t(v*sinTheta-4.9t) t= v*sinTheta/4.9
June 18, 2016

Physics
net force=mass*acceleration acceleration is zero. net force=0 thrust=dragforce 225kN=10V^2 solve for V
June 18, 2016

Algebra
imaginary roots.
June 18, 2016

science
see other post
June 18, 2016

Physics
at the max altitude, velocity is zero. Vf=vi-9.8t solve for t
June 18, 2016

science
F=c/kr^2 so F is proportional to 1/K
June 18, 2016

physics
your first statement...hass a mass of ... what are the units of that number, as it makes no sense.
June 18, 2016

Science
that was angular velocity. linear velocity= angular velocity*radius linear velocity= .05 *PI/1800 m/s
June 18, 2016

Science
it travels PI radians. Velocity=PI radians/30min*1min/60sec= PI/1800 rad/sec
June 18, 2016

Computer Science
you could add this subroutine... If Children > 7*Adults then ? That is quite a lot of children to supervise at once. Are you certain? Input answer: if Yes, then go to total price. otherwise, go in Adults?
June 18, 2016

Computer Science
algorithm Adults? Store Adults in Adults Children? Store Children in Children totaal price=13*ADULTS +8*Children If Adults +children >5, then total price=.9*total price otherwise go to finish Finish: Print: Total price
June 18, 2016

Physics
ftequency*wavelength=speed here speed=20/1=20m/s
June 18, 2016

Chemistry
2Fe + O2 >> 2FeO Fe loses electrons, it is oxidized, and therefore is a reducing agent. O gained electrons, so it was reduced, and is the oxidizing agent.
June 17, 2016

art
Or, a degree in Art or a degree in most anything, with a minor in Art, and a minor in Education with enough hours to meet the state minimum requirement...that varies by state. Some states offer a few other alternative paths.
June 17, 2016

Chemistry
for each mole of N2, one gets 2 moles of NH3 molesNH2=2*42.02/atomicmassN2
June 17, 2016

math
ABS(X-Y)=10 PICK A FEW POINTS. y=1000, THEN X=1010 OR 990 X=-37.3 THEN Y= -27.3 OR -47.3 Looks like I could pick millions, or an infinite number, of points
June 17, 2016

physical science
.16*25=(85+.16)V V=about 16*25/100*85=4/100=about .05 answer D
June 17, 2016

Mathematics
1.5Km=1500m 1500m*.000002=1.5E3*2E-6=.3m or 30cm check that.
June 17, 2016

Math
volume means measurements to the cube .112*50^3=14,000
June 17, 2016

urgent help please i have an exam !!
velocity ball=5-9.8t^2 upward.... draw the figure, if x is the distance from the pole to the shadown, one has two similar triangles 15/x=h/(x-12) where h is the height of the ball. a) 15x-180=xh but h=5t-1/2 9.8 t^2 dh/dt=5-9.8t starting with the equation a) 15 dx/dt=hdx/dt + ...
June 17, 2016

Please Help, I Don't Know How To Do This
1. reduce chef; multiply all dimensions by .5 2. for volume, dimentsions have to be cubed. 300percent is 3 times, so take all dimensions and multiply by cubr(3) (duh, thats 1.44)
June 17, 2016

SPSS
There must be more to this. It makes no sense out of context
June 17, 2016

Math (pre-celc 12)
cot + tan= cos/sin + sin/cos= (cos^2 + sin^2 )/sin*cos = 1/cos*sin= csc*sec
June 17, 2016

Calculus
Maya, I looked at your last tutors (Dr Reiny), and his answer assumed the estimation using trapazaoids, which is a better estimate of this curve. I did above assuming rectangle strips, right end points, which will underestimate the area. My guess is your teacher wants you to ...
June 17, 2016

Calculus
widths: x 0 to 1, 1 to 2, 2 to 3 right endpoints, x=1,2,3 area=height*width=(-2+6)1 + (-4+6)1 + (-6+6)1=4+2+0 check my thinking.
June 17, 2016

science
Waht is room temp? What is freezer temp? What was in the ballon..water...dry air...wet air?
June 17, 2016

rhs
moles acid=mole base
June 17, 2016

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