Wednesday
July 23, 2014

Posts by elena


Total # Posts: 4,343

phy
242 – 22.8 =219.2 mm, 100⁰ /219.2 = 0.456 ⁰/mm, 22.8 + 0.456•20=31.92 mm.

Physics
Load = ultimate strength x Area/ Factor of safety= =630•10⁶•π•0.03²/4•5=8.9064•10⁴ N= =89.064 kN

Physics
cross sectional area has to be measured in cm² or m² => A= 5.300cm² = 5.3•10⁻⁴ m² = 0.00053 m² Factor of safety = ultimate strength/allowable strength= = ultimate strength x Area/ Load = =630•10⁶•5.3•10⁻&#...

physics
ave) = total distance/ total time =s/t t=s/v(ave) = 100/20 = 5 s s=v₀t+at²/2 ….(1) v= v₀+at a= (v -v₀)/t ….(2) Substitute (2) in (1) 2s= v₀t +vt v₀ =( 2s –vt)/t =( 200 -25•5)/5 = 15 m/s a=(v -v₀)/t =(25-15)/5 = 2 m/s...

physics
ave) = total distance/ total time =s/t t=s/v(ave) = 100/20 = 5 s s=v₀t+at²/2 ….(1) v= v₀+at a= (v -v₀)/t ….(2) Substitute (2) in (1) 2s= v₀t +vt v₀ =( 2s –vt)/t =( 200 -25•5)/5 = 15 m/s a=(v -v₀)/t =(25-15)/5 = 2 m/s...

physics
ave) = total distance/ total time =s/t t=s/v(ave) = 100/20 = 5 s s=v₀t+at²/2 ….(1) v= v₀+at a= (v -v₀)/t ….(2) Substitute (2) in (1) 2s= v₀t +vt v₀ =( 2s –vt)/t =( 200 -25•5)/5 = 15 m/s a=(v -v₀)/t =(25-15)/5 = 2 m/s...

Sciences
mg = Tsinα T=mg/sinα=0.875•9.8/sin10.5 =0.817 N mv²/R = Tcosα v=sqrt{TRcosα/m} = =sqrt{0.817•3.46cos10.5/0.875} = 1.78 m/s

General physics
a= v²/R. top ma= mg –N N=m(g-a) = =m (g- v²/R) = = 34.1{9.8 - (4.23²/9.15 )}= =267 N. bottom ma=N-mg N= m(g+a) = = m (g+ v²/R) = = 34.1{9.8 +(4.23²/9.15 )}= =401 N

general physics
a) KE=mv²/2= 13900•23.5²/2 = 3.83•10⁶ J. b) KE= PE₁+KE₁ KE₁ = KE-PE = mv²/2 -mgh₁ = =3.83•10⁶ - 13900•9.8•12.5= =3.83•10⁶- 1.7•10⁶ =2.13•10⁶ J. mv₁²/2 = KE&#...

physics
v(ave) = total distance/ total time =s/t t=s/v(ave) = 100/20 = 5 s s=v₀t+at²/2 ….(1) v= v₀+at a= (v -v₀)/t ….(2) Substitute (2) in (1) 2s= v₀t +vt v₀ =( 2s –vt)/t =( 200 -25•5)/5 = 15 m/s a=(v -v₀)/t =(25-15)/5 = 2 m...

physics
a= v²/R. top ma= mg –N N=m(g-a) = =m (g- v²/R) = = 34.1{9.8 - (4.23²/9.15 )}= =267 N. bottom ma=N-mg N= m(g+a) = = m (g+ v²/R) = = 34.1{9.8 +(4.23²/9.15 )}= =401 N

Physics
a) KE=mv²/2= 13900•23.5²/2 = 3.83•10⁶ J. b) KE= PE₁+KE₁ KE₁ = KE-PE = mv²/2 -mgh₁ = =3.83•10⁶ - 13900•9.8•12.5= =3.83•10⁶- 1.7•10⁶ =2.13•10⁶ J. mv₁²/2 = KE&#...

general physics
a) the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², r=1.74•10⁶ m M=7.35•10²² kg ma=F F =G•m•M/R² ma=mv²/R G•m•M/R² =mv²/R v=sqrt(GM/R) T=2πR/v = 2π•sqrt{R...

general physics
the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², Earth’s mass is M = 5.97•10²⁴kg, Earth’s radius is R = 6.378•10⁶ m. r=R+h =6.378•10⁶ +0.327•10⁶ =... ma=F F =G•m•M/r²...

physics
L=vₒ²•sin2α/g, vₒ² = Lg/sin2α F=mvₒ²/R=m Lg/Rsin2α=2259.69 N

physics
Weight =W= mg m=W/g =491 / 9.8 =50.1 kg F = mv²/ r=173.6 =50.1•4.2²/5.09 = 173.6 N since his partner is in the straight-down position, the man also has to apply force to keep his partner from falling down due to gravity, so you have to add the partner's weig...

physics
W= mg=> m=W/g = 507 /9.8 = 51.7 kg. ma=T-mg a= T/m - g = =590/51.7 - 9.8 = 1.6 m/s² h=at²/2 t= sqrt(2h/a) = =sqrt(2•30.1/1.6) =6.13 s.

physics
http://answers.yahoo.com/question/index?qid=20090818145339AAdPF06

Physics
F=12 N

physics
ω=2π/T= 2π/24•3600= 7.27•10⁻⁵rad/s 1) equator v= ω•R=7.27•10⁻⁵•6.38•10⁶ = … m/s a=ω²•R= … m/s² 2) at a latitude of 76.0 ° north of the equator r=Rcos76.6⁰=6....

physics
v=at= 0.1g•3.15•10⁷=3.087•10⁷ m/s, s=at²/2=0.1g•(3.15•10⁷)²/2=4.86•10¹⁴m, s₁=d-s=4•10¹⁶-4.86•10¹⁴=3.95•10¹⁶ m, t₁=s₁/v = 3.95•10¹...

Physics
[Load] =N (not Pa)

physics
t=2πR/v

physics
the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², F =G•m₁•m₂/R² m₁=m m₂=5.65-m F =G•m •(5.65-m)/R² Solve for m

Phyiscs
the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², Earth’s mass is M = 5.98•10²⁴kg, Earth’s radius is R = 6.38•10⁶ m. T=L/v F = m₁•m₂/R= G•m•M/(2.07R) ² F=ma=m•v²...

Physics
φ=ω₀t-εt²/2 ω=ω₀-εt ω=0 ω₀=10π rad/s ε=1.2 rad/s² φ=2πN 0=ω₀-εt => t = ω₀/ε 2πN = ω₀t-εt²/2= =ω₀²/ε - ε...

Physics
T =>he first law states that if the net force (the vector sum of all forces acting on an object) is zero, then the velocity of the object is constant => 1. One force acts on the object.

Physics
f. Force acting down and constant This force is gravity - mg

Physics
F=ma=mv/t

Physics
e. Force acting down and constant (mg - gravity)

PHYSICS 2
KE=W=eU=1• 10⁴ eV

physics
1) ma=T-mg T=m(a+g) 2) a=0 => 0=T-mg T=mg

physics
mgsinα=μN=μmgcosα μ=tanα

physics
v=const => ΣF=0 F₁₂=sqrt(F₁²+F₂²) F₃=F₁₂ F₃(x)= -F₂ F₃(y)= -F₁ tan α= F₃(y)/ F₃(x)= =F₁/F₂ α is the angle that F₃ makes with +x direction (south of east)

physics
v=const => ΣF=0 F₁₂=sqrt(F₁²+F₂²) F₃=F₁₂ F₃(x)= -F₂ F₃(y)= -F₁ tan α= F₃(y)/ F₃(x)= =F₁/F₂ α is the angle that F₃ makes with +x direction (south of east)

Physics
a=v/t

physics
a=v²/2s= 5.5²/2•0.45 = … t=v/a=….

Physics (Stress & Strain)
Factor of safety = ultimate strength/allowable strength Allowable strength= ultimate strength/ Factor of safety= =550•10⁶/3=183.33•10⁶ Allowable strength=Load/Area => Load= Allowable strength x Area = = Allowable strength x (π•d²/4) =183...

Physics (Stress & Strain)
Allowable strength=Load/Area, Factor of safety = =ultimate strength/allowable strength= = ultimate strength x Area/ Load= =550•10⁶•7•10⁻⁴/79000=4.873

physics
vt/L=5.45•10³•111•10⁻³/91.4 =6.62

physics
http://www.god-and-science.com/physics/phy111/2009/eoc02/ch01_a.pdf Problem #27

physics
L=37 m v₁=5.95 m/s v₂=7.8 m/s L+ v₁t= v₂t t=L/ (v₂-v₁)= =37/(7.8-5.95) =20 s d= v₁t=5.95•20=119 m.

physics
N=5540 lines/cm=554000 lines/m d=1/N=1.8•10⁻⁶ m 1) m=2 tanφ₂= x₂/L=26/42.5 =0.61 φ₂=tan⁻¹0.61= 31.5⁰ sinφ₂=sin 31.5⁰=0.52 dsinφ =mλ dsinφ₂=2λ λ= dsinφ₂/m=1...

Physics
C=εε₀A/d ε=1 ε₀=8.85 •10⁻¹² F/m A=Cd/ ε₀= =3.78•10⁻¹²•0.303•10⁻³/8.85•10⁻¹²= =1.29•10⁻⁴ m²

Physics (Stress & Strain)
Shearing stress (tangential stress) τ=V/A, where V ia resultant shearing force which passes through the area A being sheared. V= τA=τ•πdh Shear force is equal to the punching force P P=τπdh= =670•10⁹•3.14•0.03•0.08 =...

Physics (Stress & Strain)
OK

Physics (Stress & Strain)
Shearing stress (tangential stress) τ=V/A, where V ia resultant shearing force which passes through the area A being sheared. V= τA=τ•πdh Shear force is equal to the punching force P P=τπdh= =670•10⁹•3.14•0.03•0.08 =...

astonomy
A=4πr²

physics
a=v²/2s =1.9²/2•7.8=0.23 m/s² ma=F(fr)=μN=μmg μ=a/g = 0.23/9.8=0.23

Physics
v₀⒳=v₀•cosα v₀⒴=v₀•sinα L=vₒ²•sin2α/g,

Please help how do I calculate this
Hot water lost Δ H₁=CmΔT₁ =4.180• 25•(51.5-35) =1724 J Cold water got Δ H₂=CmΔT₂ =4.180• 25•( 35-25) =1045 J Δ H = Δ H₁-Δ H₂=1724-1045=679 J heat capacity of the calorimeter (Calorimeter...

Physics
F=ma=mv²/2s

Physics
F=ma=mv/t

physics
pV=mRT/M => ρ =m/V = pM/RT => RT=pM/ ρþ U= miRT/2M = =mipM/2M ρ =mip/2 ρ= =1•5•80000/2•4 = 50000 J

Physics (Stress & Strain)
σ= F/A A=1•2.5=2.5 cm²=2.5•10⁻⁴m² σ= 150000/2.5•10⁻⁴=6•10⁸ N/m². Strain is defined as "deformation of a solid due to stress" and can be expressed as ε= σ/E, where E= Young’s mod...

Physic (Stress & Strain)
L=1.9 m, A= 11 cm²= 11•10⁻⁴m² F=5450 N ΔL = 2.42 mm =2.42•10⁻³ m Stress σ= F/A = 5450/11•10⁻⁴=4.95•10⁶ N/m²= =4.95 MPa Strain ε = ΔL/L= 2.42•10⁻³/1.9 =1.27•10&#...

physics
PE=mgh

physics
http://gmanacheril.com/PHY2048/Text%20Materials/Lesson%204.4%20Conditions%20of%20Equilibrium.pdf Example #2

Physics
P₁₀₀>P₂₅ => U²/R₁₀₀ > U²/R₂₅. Since U = const => R₂₅>R₁₀₀

Physics
50/km/h=13.9 m/s m•a=N•sinα 0=N•cosα - m•g m•v²/R=N•sinα = m•g•sin α/cos α =m•g•tan α tan α = v²/gR =13.9²/9.8•59.9=0.329 α = tan⁻¹=18.19⁰

physics
a=(F-R)/m = (4500-1500)/2000=1.5 m/s^2

physics
Mv₁=mu+Mv₂ u = M(v₁-v₂)/m = = 208(27.9-20.1)/45.9 = =35.3 m/s

Physics
Work =power x time

physics
v(vert) = sqrt (2gh) = =sqrt(2•9.8•0.8)=3.96 m/s

physics
d=sqrt{(8-6)²+5²}= 5.4 m

physics
n=R/A A=R/n = 0.6/1.31=0.458 m http://www.saburchill.com/physics/chapters3/0004.html

Physics
E=F/q=0.032/0.003=10.67 V/m, E= - grad φ E=Δφ/Δx= Δφ/d => Δφ=Ed= 10.67•0.04=0.427 V. ΔPE = - Work of electric field= =-q•Δφ=-0.003•0.427= -1.28•10⁻³ J. Δφ=V. C=εε₀...

Physics
F=eE=1.6•10⁻¹⁹•2805 = 4.5•10⁻¹⁶ N

Physics
ℰ=Δφ=1378 V mv²/2=qΔφ v=sqrt(2qΔφ/m)=…

Physics
the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², F₁₂ =G•m₁•m₂/y²= ... F₃₂ =G•m₃•m₂/x²= ... F=sqrt(F₃₂²+F₁₂²)=... φ is the ...

physics
Average speed = =Total distance/ total time = = 2s/{t₁ +t₂} = = 2s/{s/v₁) +(s/v₂)} = =2v₁v₂/(v₁+v₂) = =2•30•45/(30+45) = 36 km/h

Physics (Intro)
f=ω/2π =sqrt(k/m)/ 2π f=N/t=20/5=4 Hz

physics
C=εε₀A/d ε=1 ε₀=8.85 •10⁻¹² F/m A=1•1=1 cm²=1•10⁻⁴ m² C=q/U=q/Ed ε₀A/d= q/Ed q=ε₀AE=8.85 •10⁻¹²•1•10⁻⁴•1•10⁶= =...

science
c) Pascal/s law

science
a) Uranium

science
d) Gold

science
mv=(m+M)u u=mv/(m+M) = 4•10/(4+40) = 0.9 m/s d) 1 m/s

science
a) AgNO3

science
T=0⁰C = 273 K, p= 1.01325•10⁵ Pa, M=(12+16+16) •10³ = 40•10³ kg/mol. V=mRT/Mp= = 0.004•8.31•273/44•10⁻³•1.01325•10⁵= =0.00204 m³= 2.04 L

Physics
W = m•g =G•m•M/R² g= G•M/R² the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², Earth’s mass is M = 5.97•10²⁴kg, Earth’s radius is R = 6.378•10⁶ m.

physics
PE=KE+PE₁ mgH = mv²/2 + mgR v²= 2g(H-R) at point A N=mv²/R =2mg(H-R)/R= =2•4.3 •10⁻³•9.8•(0.8-0.31)/0.31 = = 0.133 N

Physics
Δh= 13•4.47 m ΔPE =mgΔh = 86.9•9.8•13•4.47= =49487.6 J

physics
F =G•m₁•m₂/R² the gravitational constant G =6.67•10⁻¹¹ N•m²/kg²,

physics
υ = 1.5 mol p= 3 atm = 303975 Pa V=7 L = 0.007 m³ R=8.31 J/mol•K T=? pV= υRT T=pV/υR= =303975•0.007/1.5•8.31=170 K

physics
the gravitational constant G =6.67•10⁻¹¹ N•m²/kg², Earth’s mass is M = 5.97•10²⁴kg, Earth’s radius is R = 6.378•10⁶ m. r = 850000 m ma=F mv²/(R+r)= G•m•M /(R+r)² v=sqrt{G•M /(R+r)...

physics
Wavelength = speed/frequency

physics
I=q/t q=Ne t=2πR/v I=Nev/2πR= =10¹¹•1.6•10⁻¹⁹•3•10⁸/2π•300 = =0.0025 A

physics
v=v₀-gt v=0 t=v₀/g=14/10=1.4 s

physics
λ= 630•10⁻⁹ m, d= ? μm = ? •10⁻⁶ m L=4 m k=1 x=? d•sin φ =k•λ sin φ=k•λ/d φ=sin⁻¹(k•λ/d) tan φ= x/L x=L•tan φ

Physics
s=v²/2a

physics
H-h= gt²/2 t=sqrt{2(H-h)/g} = =sqrt{2(51.5-12.9)/9.8}=2.8 s. v=gt =9.8•2.8=27.44 m/s h₁=12.9 – 1.6 =11.3 m h₁=vt₁+gt₁²/2 gt₁² + vt₁-h₁= 0, t₁² + 27.44t₁- 11.3 = 0, t₁² + 2.8t₁-...

Physics
Δh=H-h= gt²/2 t=sqrt(2•Δh/g)= =sqrt{2• (3520-1760)/9.8}=18.95 s. s=vt=10•18.95=189.5 m

Physics
t=s/v=2300/320=7.1875 h

Physics
initial position d₀=0, The maximum height at the motion with initial velocity v₀=20 m/s is H=v₀²/2g=20²/2•9.8 = 20.4 m (!!!) H=v₀t-gt²/2, v(fin)= v₀ -gt, v(fin)=0, => 0= v₀ -gt => v₀ =gt, H=gt²-gt²/2...

Physics
Electric field on the axis of the ring at the distance ‘x’ from the center of it is E = k xq/{sqrt(R²+x²)}³ k=1/4πε₀ The test charge is in equilibrium => E₁=E₂ k x₁q₁/{sqrt(R²+x₁²)}³= =k x...

physical science
Buoyant force=Weight ρ•V₁•g = Weight V₁=x•y•z₁ ρ•x•y•z₁•g = Weight z₁=Weight/ ρ•x•y•g = =445/1000•4•3•9.8=0.0038 m =3.8 mm

physics
The second law for rotation M=Iα => α=M/I M₁/I₁=M₀/I₀ => M₁/M₀=I₁/I₀ I₁ = I₀ => M₁ = M₀ F₁x₁=F₀x₀ F₁/F₀=x₀/x₁=x₀/2x₀ =1/2

Physics
The reflectivity R represents the fraction of the incident light that is reflected at the interface R=I/I₀, where I₀ and I are the incident and reflected beams intensities respectively. If the light is normal (or perpendicular) to the interface, then R={(n₂-n...

physics
tangent to the path

Physics
Suppose that the bullet hits the aim at the upward motion, then h= v₀₁•sinα•t - gt²/2 = v₀₂•sinβ•t - gt²/2, v₀₁•sinα = v₀₂•sinβ , sinβ= v₀₁•sin^...

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