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August 2, 2015

Posts by Elena


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Physical Science
#4
April 28, 2013

chem (boyles and charles law)
T₂=V₂T₁/V₁
April 28, 2013

chem. mix of boyles and charles law
V₂=T₂V₁/T₁ 1 atm = 101325 Pa 1 L = 10⁻³ m³
April 28, 2013

chemistry (charles law)
V₂=T₂V₁/T₁ T₁=303 K T₂=273 K
April 28, 2013

chemistry (charles law)
V₂=T₂V₁/T₁
April 28, 2013

physics
Given data: 1st rod: L₁, T₁, x₁, a => A₁=a²; 2nd rod: L₂, T₂, x₂, d => A₂= πd²/4; Hook’s Law for rods: σ=Eε T/A = E•x/L, 1st rod: T₁/a²= E•x₁/L₁, 2nd rod: 4T&#...
April 28, 2013

Science
m=D•V
April 28, 2013

Physics
m=39.0 kg s=4.5 m, F=135 N, μ=0.3 (a) W(F) = Fs (b) ΔU= W(fr) = μmgs (c) W(N) = 0 (d) W(mg) = 0 (e) KE=W(F) –W(fr) =Fs - μmgs (f) KE=mv²/2 v= sqrt(2•KE/m)
April 28, 2013

physics
The sums of torques respectively the edges of the board are: W•x-400•2 = 0 W• (2-x) -700•2=0 W•x=800 2W-W•x -1400 = 0 2W-800-1400=0 W=1100 N x=800/W =0.73 m
April 28, 2013

physical science
(A)tetrahedral This distorted tetrahedral arrangement is call bent. http://www.ausetute.com.au/shapemol.html
April 28, 2013

physics
h=s•sinα=v•t•sinα=1.5•21•sin30=15.75 m
April 27, 2013

physics
p=sqrt{p(x)²+p(y)²} = = sqrt{(10•9) ² +(20•12)²}=256.32 kg•m/s v= p/(m₁+m₂) =256.32/30 =8.54 m/s
April 27, 2013

physics
k =9•10⁹ N•m²/C² r=0.18 m q₁= 5•10⁻⁹ C q₂ = - 2•10⁻⁹ C PE= k•q₁•q₂/r = ...
April 27, 2013

physics
φ =198t-24t²-2t³ (a) ω=dφ/dt=198 -48t-6t², ω=0 => 198 -48t-6t²=0, 6t²+48t-198=0, t²+8t – 33 =0, t= -4±√(16+33 ) =-4±7, t=-11 (impossible), t=3 s. (b) ε=dω/dt= - 48 -12t. t=3 => ε=-...
April 27, 2013

Physics
F=qE=eE => E=F/e=3•10⁻¹⁵/1.6•10⁻¹⁹= 1.875•10⁴ N E=Δφ/Δx= Δφ/d => Δφ=Ed=1.875•10⁴•0.2=3.75•10³ V
April 27, 2013

Physics
mg=kx x=mg/k=2.35•9.8/1.64•10³=0.014 m
April 26, 2013

Physics
F=k•q₁•q₂/r², k =9•10⁹ N•m²/C², q₂ = F•r²/k•q₁ = 1.8•0.3²/9•10⁹•6•10⁻⁶ = =3•10⁻⁶ C = 3 μC Due to the attraction of the charges q&#...
April 26, 2013

Physics
F=k•q₁•q₂/r²= k•q²/r² q=sqrt{ F•r²/k}=sqrt{7•10⁻⁹•(3.2•10⁻¹⁰)²/9•10⁹}=2.82•10⁻¹⁸C
April 26, 2013

Physics-- please help me finish!!
m₂g=kx k= m₂g/x=0.363•9.8/0.026 = 136.8 N/mþ T=2π•sqrt(m₁/k) = =2π•sqrt(1.4/136.8)=0.64 s
April 26, 2013

physics
L=Iω=mR²ω =0.5•1.45²•1.5 = 0.29 kg•²/s
April 26, 2013

physics
fluorine gas F₂=> μ = 36 g/mol =36•10⁻³ kg/mol, m= 0.076 kg, V=1.5 L = 1.5•10⁻³ m³, t= -37℃ = 236 K, pV=mRT/ μ => p =mRT/ Vμ =0.076•8.31•236/1.5•10⁻³•36•10⁻³= =...
April 26, 2013

Physics SI unit
Newton
April 25, 2013

physics
F₁=mv²/R₁ F₂=mv²/R₂=mv²/2R₁=F₁/2
April 25, 2013

Physics
B=sqrt{B(y)²+B(z)²} = =sqrt{0.5²+0.67²} = 0.836 T, F=qvBsinα, sinα=1, F=qvB=31•10⁻⁶•62•0.836=1.6•10⁻³ N. Vector B makes an angle β with z-axis: tanβ =B(y)/B(z) =0.5/0.67=0.746, β=36.7° ...
April 25, 2013

physics - stopping distance
The reaction time is t =x/v=7.5/10 = 15/20 =22.5/30 = 0.75 s. The reaction distance for v=25 m/s is x=vt=25•0.75 = 18.75 m. The acceleration is a=v²/2s=10²/2•5=20²/2•20=30²/2•45=10 m/s² The breaking distance for v=25 m/s is s= v&#...
April 25, 2013

physics
F=ILB B=F/IL
April 25, 2013

physics
mgh=mv^2/2, v=sqrt(2gh) = ...
April 25, 2013

physics
F=qvB =evB v=F/eB=...
April 25, 2013

physics
engine’s efficiency=A/Q =417/848=0.49 or 49%
April 25, 2013

Physics
A) L=λ/2=v/2f B) L=λ/4=v/4f v is the speed of sound
April 25, 2013

Physics
φ=ω₀t±εt²/2 ω=ω₀±εt ω=2πn ω₀=2πn₀=0 φ=εt²/2 2πn= εt ε=2πn/t φ=εt²/2=2πn t²/2t= πn t=3.14•30•5=...(rad)
April 24, 2013

Physics
mg(H+h)=mv²/2 v = sqrt{2g(H+h)}
April 23, 2013

Physics
p=ρgh+p₀ = 1025•9.8•10300+101325 =103564825 Pa F=pA=pπr²=103564825•π•0.13²=5.5•10⁶ N
April 23, 2013

Science/DUE TODAY
http://wiki.answers.com/Q/What_3_changes_polar_bears_would_need_to_change_to_live_in_the_desert
April 23, 2013

Quantum Physics
1/λ =R(1/n² - 1/m²) = =1.1•10⁵(1/1²-1/∞) λ = 9.1•10⁻⁶ m
April 22, 2013

Math
10/(3x) + 4/3 = (7+x)/2x 20+8x=21+3x 5x=1 x=1/5
April 22, 2013

Physics Eletric fields and coulomb's law)
E=ke/r², r=sqrt(ke/E) = = sqrt(9•10⁹•1.6•10⁻¹⁹/2.02•10⁻⁷)= =8.44•10⁻²m
April 22, 2013

Math PLEASE HELP!
What is the base of your logarithms? If it is common logarithm logx=log₁₀x=3.5829 => x=10³•⁵⁸²⁹=3827.366 If it is binary logarithm logx=log ₂x=3.5829 x=2³•⁵⁸²⁹=11.983. If it is natural ...
April 22, 2013

physics
The gravitational constant G =6.67•10⁻¹¹ N•m²/kg², h=100000 m m=1040 kg Earth’s mass is M = 5.98•10²⁴kg, Earth’s radius is R = 6.37 •10⁶ m. (a) F =G•m •M/(R+h)² (b) a= G• M/(R+h)²...
April 22, 2013

science
http://en.wikipedia.org/wiki/Thermal_conduction
April 22, 2013

Physics
B=μ₀I/2πb=1.25664•10⁻⁶•1.24/2π•0.436 =5.69•10⁻⁷ T
April 22, 2013

physics
F=qE=eE=1.6•10⁻¹⁹•341•10⁵=5.456•10⁻¹² N
April 22, 2013

Physics
cosα=1, ℇ=ΔΦ/Δt = N•Δ(B•Acosα)/Δt= =N•A•ΔB/Δt, ℇ=I•R, N•A•ΔB/Δt= I•R, I= N•A•ΔB/Δt•R= =347•0.28•2.4/0.31•49 = 15.35 A
April 22, 2013

physics
cosα=1 ℇ=ΔΦ/Δt = N•Δ(B•Acosα)/ Δt= =N•A•ΔB/Δt ℇ=I•R N•A•ΔB/Δt= I•R I= N•A•ΔB/Δt•R= ...
April 22, 2013

PHYSICS!!!!...PLEASE HELP
v=const => mgsinα=F(fr) = μN= μmgcosα sinα= μcosα μ=tanα
April 22, 2013

physics
mgh=kx²/2 x=sqrt(2mgh/k)
April 21, 2013

Science
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving the atom a net positive or negative electrical charge.
April 21, 2013

Physics
The object located between F and 2F => the image will be located beyond the 2F point on the other side of the lens. It is real, inverted and its dimension is larger than the object demension. d₀ - object distance d₁ - image distance f- focal lenth 1/d₀ +1/...
April 21, 2013

Physics *Electrical Scientist* please help me!!!
http://www.tutorvista.com/science/jj-thomson-atomic-theory-0 http://en.wikipedia.org/wiki/Cathode_ray_tube
April 20, 2013

calculus
t=∛x =x^(1/3) => y=3x^5 = 3x^(5/3). dy/dx =3•(5/3)•x^(2/3) = =5 •125^(2/3)=525=125
April 20, 2013

Physics
d₀ - object distance d₁ - image distance f- focal lenth 1/d₀ +1/d₁ =1/f, 1/d₁ =1/f - 1/d₀ = = (d₀-f)/ d₀•f, d₁=d₀•f/(d₀-f)= =0.4•0.15/(0.4-0.15)=0.24 m, 0.03/0.4 =h/ d₁ , h= d₁•0....
April 20, 2013

Physics
mgsinα=F(fr) = μN= μmgcosα sinα= μcosα μ=tanα
April 20, 2013

calculus
s= 189t- t³ v=ds/dt = 189-3t² t=0 = > v=189 m/s. 189-3t² = 0 t=√(189/3) =√63 = 7.94 s. s=189 t- t³= =189(7.94) -7.94³=1000.1 m a=dv/dt =d(189-3t²)/dt= - 6t t=8 => a= - 6•8 = - 48 m/s²
April 20, 2013

physics
I=2mR²/5 ω=2π/T KE= Iω²/2
April 20, 2013

Physics
m₁gh= m₁v₁₀²/2 => v₁₀=sqrt(2gh) m₂gh= m₂v₂₀²/2 => v₂₀ =sqrt(2gh) m₁v₁₀ - m₂v₂₀= - m₁v₁ + m₂v₂ v₁= {-2m₂v₂₀...
April 20, 2013

Physics
C)λ, ν, and 100E
April 20, 2013

calculus (gr 12)
f(x) = 2x³+4x²-5x+8 f′(x) =6x²+8x-5 f′(-2) = 2(-4) ² +8(-2) -5 = 11
April 19, 2013

calculus
f(x) =x⁴-3x f′(x) = 4x³ -3 => f′(3) = 4•3³ -3= 105
April 19, 2013

calculus (gr 12)
s= 189t- t³ v=ds/dt = 189-3t² t=0 = > v=189 m/s. 189-3t² = 0 t=√(189/3) =√63 = 7.94 s. s=189 t- t³= =189(7.94) -7.94³=1000.1 m a=dv/dt =d(189-3t²)/dt= - 6t t=8 => a= - 6•8 = - 48 m/s²
April 19, 2013

physics
X: ma=Fcosα-F(fr) Y: 0=-mg+N+Fsinα =>N=mg-Fsinα F(fr) = μN=μ(mg-Fsinα) ma= Fcosα- μ(mg-Fsinα) a = { Fcosα- μ(mg-Fsinα)}/m
April 19, 2013

physics
S=(v-v₀)•t=(2-1) •3•60= 180 m
April 19, 2013

physics
F₁=k•q₁•q₂/r₁², F₂=k•q₁•q₂/r₂², F₁/F₂=k•q₁•q₂•r₂² / k•q₁•q₂•r₁², F₂= F₁• r₁²/r &#...
April 19, 2013

Physics
T₁=2πsqrt(m₁/k) T₂=2πsqrt(m₂/k) T₁/T₂=sqrt{m₁/m₂} T₂=T₁/sqrt{m₁/m₂}= 2.8 s
April 19, 2013

Physics
λ=v/f =3•10⁸/6•10¹⁶=5•10⁻⁹ m
April 19, 2013

Literature ?! Check my answers?
CCB! just took test too!
April 17, 2013

Physics :)
Angular acceleration= torque/moment of inertia
April 13, 2013

physics
T + mg = mv²/R => T = m (v²/R -g)
April 13, 2013

physics
Tsin(α/2)=kq²/{2Lsin(α/2)}², Tcos(α/2)=mg. tan(α/2)= kq²/mg{2Lsin(α/2)}², m= kq²/g{2Lsin(α/2)}²•tan(α/2)=...
April 13, 2013

physics
m₁gh₁ =mv²/2, v=sqrt(2gh₁)=… m₁v=(m₁+m₂)u, u= m₁v/(m₁+m₂)=.. . (m₁+m₂)u²/2=(m₁+m₂)gh₂, h₂=(m₁+m₂)u²/2(m₁+m₂)=..
April 13, 2013

physics
h=gt²/2 t=sqrt(2h/g) =sqrt(2•200/9.8)=6.39 s
April 12, 2013

Physics
a) density b) acceleration c) - d) - e) refractive index f)capacity g)resistance h) pressure
April 11, 2013

physics
a=F/m=90/(40+3) = 2.1 m/s2
April 11, 2013

physics
ma=F(fr), mv²/R =μmg, v=sqrt(μRg) = sqrt(0.63•39.6•9.8)= …
April 11, 2013

physics
F(x) =-F(1x) +F(2x)+F(3x) – F(4x) = =(G•m₅•cos45°•2/s√2)•(-m₁+m₂+m₃-m₄)=... F(y) = F(1y) +F(2y)-F(3y) – F(4y) = =(G•m₅•sin45°•2/s√2)•( m₁+m₂-m₃-m₄...
April 11, 2013

Physics!! HELP
λ=2•2.5=5 m s=14•5=70 m v=s/t=70/15=4.67 m/s
April 11, 2013

Physics
An object is placed 11 cm in front of a concave mirror whose focal length is 23 cm. The object is 3.6 cm tall. Determine (a) the location of the image, taking a real image as a positive value and a virtual image as a negative value. (b) Determine the height of the image, where...
April 11, 2013

Physics Hear
1) Q=c•m•ΔT=4183•10•(100-20)=3346400 J 2) Q=Lm = 2260000•0.01 = 22600 J 3) Q= Q₁+Q₂+Q₃= c₁•m•ΔT₁+rm+ c₂•m•ΔT₂= =2060•3•7+ 335000•3+4183•3•25 = =43260...
April 11, 2013

physics
http://en.wikipedia.org/wiki/Snell's_law
April 11, 2013

Physics
a=v/t=20/25 = ...
April 11, 2013

physics
Please see the Related Questions below
April 11, 2013

Physics
n=actual depth/apparent depth = =3/(3-1.1) = 3/1.9=1.58
April 10, 2013

physics
P=(m₁+m₂)g/A=(40+12) •9.8/2(6•4)•10⁻⁴=106167 Pa= 106.167 kPa
April 10, 2013

physics
v(ave) =total distance/ time taken = =(210+470+150)/(25+20+30) = 11.7 m/s
April 10, 2013

Physics
n₁ = 1.520 n₂= 1.538 n₁=sini₁/sinr₁ n₂=sini₂/sinr₂ sinr₁=sinr₂ sini₁/n₁=sini₂/n₂ sini₂=n₂•sini₁/n₁=1.538•sin 20.97/1.52 =0.3621 i₂=21.23°
April 10, 2013

physics
p=mv
April 7, 2013

physics
(a) v=at=0.3•15=0.45 m/s (b) v₁=30km/h=30000/3600 =833.3 m/s t₁=v₁/a=833.3/0.3 =2777.8 s. (c) s=v₁²/2a= 833.3²/2•0.3=1157314 m =1157 km
April 7, 2013

physics
F= F(fr) + mgsinα= =32.6 +63.8sin59=87.3 N
April 7, 2013

physics
1T=10000 Gauss B=0.02•10⁻⁴= 2•10⁻⁶ T v=8 km/s=8•10³ m/s U=BLv= 2•10⁻⁶•4828• 8•10³=77.25 V
April 7, 2013

Physics
ℰ=-dΦ/dt=-d(NBAcosωt)/dt= =NBAωsinωt = =500•0.05•0.05•20•sin30° =12.5 V
April 6, 2013

Physics (Algebra-based)
PE → KE1 KE1 → Work(fr) +KE2 => PE → Work(fr) +KE2 If the initial height is ‘h₁’, the height of the horizontal section is ‘h₂’, the length of the rough section is ‘s’, then mg (h₁-h₂)=μmgs +mv²...
April 6, 2013

physics
vt=at²/2 t=2v/a=2•19.4/3.2=121.25 s=2.02 min
April 6, 2013

physics
ℰ=-dΦ/dt=-d( BAcosα )/dt cosα=1 ℰ =BA/t= Bab/t=Bb(a/t)=Bbv= =0.125•0.045•4.3=0.024 V
April 6, 2013

physics
ma=F => a=F/m=2/2.5=0.8 m/s² v=v₀-at v=0 t=v₀/a=0.6/0.8=0.75 s.
April 6, 2013

physics
During acceleration (or deceleration) of the bus, she continues to move in previous derection due to inertia, and, therefore, she may fall down.
April 6, 2013

physics
Energy =Power x time =680 W/m2 x 1 second =680 Joule/m2 Energy of 1 photone = hf =hc/λ Number of photones =Energy/energy of 1 photon = N=680• λ/hc=680•478•10⁻⁹/6.63•10⁻³⁴•3•10⁸=…
April 6, 2013

Physics
(a) Torque is M=p⒨•B•sinα p⒨=NIA If M(max) =sin α=1 M(max)=NIAB, I= M(max)/NAB = =40/250•0.12•0.04•1=33.3 A (b) ℰ=-dΦ=-d(NBAsinωt)/dt= =-NBAωcosωt ℰ(max)=NBAω=2πNBAf= =2π•250&#...
April 6, 2013

physics
(a) I =cε₀E²/2 =3•10⁸•8.85•10⁻¹²•(7.9•10⁻⁶)²/2=8.2•10⁻¹⁴W/m² (b) P=I•A=I•πD²/4=8.2•10⁻¹⁴•π•2.1²/4=2.84•...
April 5, 2013

physics
PE=mgh=10•2=20 J. PE->KE
April 5, 2013

physics
Question????
April 4, 2013

Physics
The speed at the 5-m level is of the same magnitude on the way up and on the way down=> s=(v²-v₀²)/2g Solve for v₀
April 4, 2013

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