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Posts by bobpursley

Total # Posts: 44,556

Writing
I am uncertain what you want here with this writing. comments: a. It has a lot of grammatical errors b. To me, it seems disjointed and lacks development of thought. I am unsure of even the basic storyline. c. The closing seems far from connected to the first few paragraphs, ...

math
I agree with Ms Sue, you did a sloppy job of proofing if done at all.

math
I think you have two cones, same top, same shape, one ending at the top, the other ending at the bottom. You have the ratio of radii and the difference in volumes. The difference in heights of the two cones is 14cm. volumetop=1/3 PI*r^2(h) volumebottom=1/3 pi(2r)^2(h+14) no ...

physics
E=sigma/epsilion sigma is charge/m^2

science
https://www.youtube.com/watch?v=l5CYNs7ze6U

Science
falling stone: hf=49-4.9t^2 rising stone: hf=0+40t-4.9t^2 set the equations equal (hf=hf), and solve for time t, then put that t into either of the original equations and solve for hf.

Science
heat=Lf*mass 37E6*370=Lf*mass so use heat of vaporization Lf in J/kg

College PHYsics
a: no resistance, vf=g*t change speed to m/s vf=1357.64km/hr*1hr/3600sec*1000m/1km vf=377.1 m/s t= 377.1/9.8=38 seconds with no air resistance <how long did it actually take to reach the speed?> avg speed= distance/time=38.96km/259sec=150m/s so you can figure the average...

Physics
k=300N/.05m=6000 N/m work done= PEmax-PEmin = 1/2 k (.12^2-.10^2)

maths
It appears you are answer grazing, value.

College Physics
a. acceleration is due to gravity, g in the downward direction b. the velocity caught.. vcaught^2=voriginal^2 -2*g*heightabove solve for vcaught. c. avg velociy= (vorig+vfinal)/2 time=distance/avgvelocity

physics
looks like 3mS, and 4mE displacement= 5m

Science
average speed in block= 10m/s time to go .1 m n block= .1/10m/s=.01sec force*time= changemomentum and change in momentum is massbullet*20m/s so you need mass bullet

Physics
No name: ARe you looking for answers to turn in and don't wnat your teacher to know? That is rather gutless. hf=hi+vi*t+1/2 g t^2 0=80+12m/s*t-4.9t^2 solve for time t, with the use of the quadratic equation. Speed: Initial PE+initial KE= finalKE mg*80+1/2 m 12^2 = 1/2 m vf...

Inverse Functions
ThetaElevation= arcTan(362/550)

Math
geomea sqrt(sqrt(2*8))=2

Chemistry
a. find the energy of the 190nm photon, you have the right formula. Now subtract the threshold energy (E=h f). With the remainder, you have ke. b. correct, use E=1/2 m v^2 c. correct formula...

physic
I agree with Scott, the specific heat of water is 4.18Kj/Kg (or aboaut 4.2kg/kg so that heat would be 4.2kg/kg*2kg*75, that then is added to the heat of fusion (melting).

Phy
Look at this ... https://www.physicsforums.com/threads/magnetic-field-of-rotating-sphere.482886/

Science (physics)
acceleration= changevelociyt/time=28/4 m/s^2 distance: avg speed=14m/s, time is 4 seconds disistance=avgspeed*time

Physics 2
add the following heats: heat to change ice at -10 to 0C heat to melt ice at 0C heat to heat water from 0C to 20C

Physics 2
the sume of heats is zero... Heat to heat water + heat or condense steam+heat to cool steam=0 200*cw*(50-20)+Hv*m + m*Cw*(50-100)=0 solve for mass m.

Physics
index=speed light in vacumn/speedLightInMaterial what is 3/1.8?

Kabir
Use your name if you intend to post here.

chemestry
CaBr2(aq)+2AuClO4(aq) ? 2AuBr(s)+Ca(ClO4)2(aq)

science
yes, my eyes are failing.

science
Wonder who would offer that as a "sample"? Molarity: grams/molmass*volumeInLiters so if you had one liter of this stuff, you so assume 1 liter of this stuff, which is 1100g .15*1100/98*1=165/98 Moles/liter Normality= 2*molarity Molality=.15*1100/98*1.1

chemistry
PV=nRT n/V=P /RT n/V; but n=mass/molmass*volume, so density/molmass=n/V n/V=density/molmass then molmass=density*RT/Pressure put in NTP, and you have it.

chemistry
grams of anacid= .17(volumestomach)*molmassAnacid

Physics 1
Is this what you want to calculate? 10*sin(2*35)*1/9.81 Lets look: time in air: hf=hi+vi*sin35*t-4.9t^2 t(10*sin35deg - 4.9t)=0 timeinair= 10sin35/9.8 now, horizontal distance: distance=10cos35*timeinair distance=10*cos35*10*sin35/9.81 = 100cos35deg*sin35deg *1/9.81 which is ...

Physics
vf^2=vi^2+2ad 0=6^2+2*(-2)d solve for distance d. how long? avg speed * time= distance 3 m/s * time=d time= d/3

Time rates
from the triangle: 20^2=h^2 + x^2 h is vertical height, and x is distance base. take the derivative... 0=2h dh/dt + 2x dx/dt dh/dt=-dx/dt x/h = 1 * 4/h where h= sqrt(400-16)

Science
http://www.askiitians.com/iit-jee-structure-of-atom-and-nucleus/solved-examples-of-structure-of-atom/ see problem 1.

Physics 11
all correct

Physics
ball1: h=200-4.8t^2 ball2: h=40*t-4.8t^2 subtract the equations. 0=200-40t t= 5 seconds where? h=200-4.8*5^2

Physics 11
draw a ray diagram to confirm your work.

Physics
There are several good explanations/demonstrations here: https://www.youtube.com/watch?v=8PcWjxuIs9o

Chemistry
Good.

Research Methodology and Program Evaluation
relating to the scientific description of peoples and cultures with their customs, habits, and mutual differences... Women qualify as subjects for ethnographic study. Ethnographic study: relating to the scientific description of peoples and cultures with their customs, habits...

Physics
hf=hi+vi*t-1/2 g t^2 hf=hi=0 t(vi-gt/2)=0 t=0 t=2vi/g t= 2*120/50=you do it.

Algebra 1
-1/(2xy^3)^5 -1/(32x^5y^15) C is correct.

Algebra 2
think not on B.

math
Whatever the market will bare. Most would think the annual divided by 12 months....In reality, it is more than that.

Physics
Ok, I am visulizing two inclines back to back, with a pulley at the top, and masses on each side. on each block, the gravity component DOWN the plane is mg*cos35 No resistive force (friction). so first, find the motion. Net force=(14-5)*9.8*cos35 twoward the greater mass. net ...

Physics
Don: I don't think the mass leaves nor goes below the surface because of weight and the surface is hard, so the only acceleration can be horizontal, no component downward. If the tension were greater, it could have went upward.

Physics
1183*cos40=106*acceleration your teacher is too easy, should have added friction.

Science
is there some particular reaction you have in mind?

Physics
Upi meed aor density, density of air is 1.20 kg/m^3 The net lift per wing area, using the Bernoulli equation, is (1/2)(air density)[(Vtop)^2-(Vbottom)^2] = ...... So that is lift per m^2, and you have 50m^2

Physics
the bouyant force depends on water displaced. The buoyant force on the wood is equal to the mass of the wood. The aluminum is denser than the wood, lets say 4 times. volume of aluminum=1/4 volume of wood. Lets pretend the wood has .6 volume submerged, so the volume of aluminum...

Physics
force=mass*v^2/r so the thrusters stop movement in the original direction, and recreate it in the perpendicular direction. workdone=1/2 mv^2 + 1/2 mv^2=mv^2 work done E=force*distance = mv^2/r * r+ mv^2/r *r=2mv^2 E/T=4 check my thinking

Physics
It matters what the angles are.

math
Hmmmmmm

College Chemistry
heat=masswater*c*deltatemp = 86.3g*4.184J/gC*(31.8-17.4) of course, this assumes you know the density of water to be 1g/ml

Physics
x=force/k so if you increse force by 2x, stretch will be 2x, or 5cm*2=10cm

Science
ghost host+g

math
Lord, it is a rate problem Rate problem: quantity=rate*time calories=320cal/hr * timeinhours

physics
time to fall h meters h=1/2 g t^2 or t= sqrt(2h/g) now, time to traverse that distance horizontally in time t. s=v*t solve for v but v^2=2*d*a1 or s= sqrt(2d*a1)*sqrt(2h/g) s=sqrt(2d*a1*2h/g) check my thinking

physics
http://www.jiskha.com/display.cgi?id=1497452479

physics
https://www.quora.com/If-the-wire-of-resistance-is-stretched-to-the-double-of-the-length-then-new-resistance-will-be-what

Physics
it point will accelerate, or the point will push back with an equal or opposite force.

physics
What is 3/5 * 200N ?

physics
number=current/e where e is the charge per electron speed: 1/2 mv^2=20E3*e m is mass of electron solve for v

Physics
total energy=max pe 1/2 m 14^2+m*g*29=mgh solve for max height h

physics
see other post

Physics
heat=power*time mc*deltaTemp=power*time 1.5kg*c*80C=1.5j/hr*timeinhours so you need c in Joules/kgC and solve for time in hours.

phy
a. time to fall: h=1/2 g t^2 t= sqrt(2h/g)=you do it horizontal distance: timetoFall*1.70 b. t=time above * sqrt(1/12) horizontal distance=1/12*origwideth*v solve for v. you did not give the original sidewalk width.

algebra 1
You need to be specific on the problem you are stuck on. We have no idea what your unit 6 includes.

Math Explain
put the terms in normal order: 18x^2 + 6 + 4x - 15x^2 - 4 + 13x 18x^2 - 15x^2 + 13x + 4x +6-4 now combine like terms 3x^2 +17x + 2 Unless you made a sign error, I dont agree with what you "know" is the answer.

Jiskha
It reminded me of Sunday Church, and the devil himself giving a sermon. I didn't remove it, but thought on it. Our site is not for chat about schools (including cheating at Connections). We try to help students with concepts, not supply answers. We are not for cheating, ...

Physics 11
Yes, if the friction involved in attaining different speeds was the same....in real life, it is not. Friction of air is dependent on velocity squared as a rule of thumb.

Physics 11
No, the work done was the difference in kinetic energies, assuming the work to overcome friction at each speed was constant.

Physics 11
the net force on the ball is only from gravity, mg. Remember, even half way upwards, it is still accelerating downward due to the force of gravity.

physics
1/2 m v^2 * .8=mcDeltaTemp DeltaTemp=.4*180^2/128 notice mass of the bullet divides out, so no change of units is needed for specific heat.

physics
I agree, law of cosines is the way to go.

chemistry: Plumpycat
Plumpy. This only works if you treat each side as absolute values. The better way to work this is to realize the SUM of the heats gained is zero (one gains, one loses). mc ?T (copper) + mc ?T (water) =0 That way, the math works perfectly.

Math
it is half way between 0 and 8.

Physical science
blood can be filtered, or centifruged, separating its components. Concrete is not a heterogenous mixture: look at the pebbles in it. Milk has fat that floats to the top.

Physics
This is a bit tricky. air resistance is indeed dependent on velocity squared. initial KE=final height- friction work 1/2 m 7^2=mgh - friction friction losses: during falling, F=ma=m(dv/dt) but we know F=mg-kv^2 or m(dv/dt)=mg-kv^2 so now you have a differential equation in v. ...

Electives
I have a degree in such: It came out of the operational analysis field in the 1960s, then moved to be called systems analysis (Univ of S. Calif), and part of that study is the interface of humans and organizations on systems to get things done. One of the better seminars I ...

science 7b tecca
Usually, it is cycling of stress as occurs in seasonal freezing.

science
subtracting the bottle mass water=50g X=30 g so the density of the liquid X is 30/50 times the density of water.

physics
http://www.cpp.edu/~skboddeker/131/131hw/ch12h.htm

Physics
work=PENew-PEold = kqq/.12-kqq/.06 q is the charge on each of the charges or qq=50E-12 Of course, you could also realize the distance is being halved, so work=2kqq/.12

social studies
Is it possible you did not look at the picture?

Physics
Assume on rebound they have the following velocities: large ball: V, in upward direction small ball: V, in downward direction you can calculate V from the height of the drop. Assume conservation of momentum, and if needed, conservation of energy. Momentum MV-mV=M*0+mV' V&#...

Physics
WEight=21kg/m^2 * 9.8N/kg*(.09m)^2

math
What is the quadratic equation?

Science
4H2O (g)+3Fe(s)>>>Fe3O4(s) +2 H2(g)

Chemistry
alocohol is easy toevaporate, however, its sturcture (helping attache itself two water molecules) allows the water there to go with it.

physics
See example 3. https://books.google.com/books?id=BukDAAAAMBAJ&pg=PA1433&lpg=PA1433&dq=a+simple+pendulum+has+a+period+of+2.0s+and+magnitude+of+swing+5cm.find+i-the+velocity+of+the+bob+ii-the+acceleration+of+the+bob&source=bl&ots=gDxmNuClKx&sig=agV4IL0lNHcEuDWK8urzpBYLHkA&hl=en&...

physics
Yes, the the final temp will be larger, due to the lost absorbance capacity of the water in the calorimeter.

science
sea water glass air

Non
I don't know about race, but in this fast-paced information age, one can get dumb and dumber by not reading current literature. It takes effort and work to stay ahead.

Math
and the told riddle of moving to the door, 1/2 way, the 1/4 way, then 1/8 way...does she ever reach the door?

Pre-Calculus 12
2 is log100 log 3^4+ log100 log(100*3^4) log (ab)=loga + log b

Engineering Systems
Or, besides lever or screw, one can use hydraulic force (see Pascal's principle)

PHYSICS
What is 10*cos30?

science
Nonsense is rampant.

Physics
??? what do you mean "base of center"? Flux thru what surface?

Chemistry
What compound are you thinking of?

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