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August 1, 2014

Posts by Elena


Total # Posts: 4,343

Physics
light reflected from the surface of a dry asphalt roadway

physics
The guage pressure at the height h = ρgh the atmospheric pressure = 1.013•10⁵ Pa ρgh•760/1.013•10⁵ =1030• 9.8•0.61•760/1.013•10⁵=46.2 mmHg

phisics
(a) ΔKE=ΔPE KE(B)-KE( A)=PE(A)-PE(B) mv²/2 -0 =mgh(A)-mgh(B) v=sqrt{2g[h(A)-h(B)]} (b) KE1/KE2 = {m1•gh(A)-mgh(B)}/ {m2•gh(A)-mgh(B)} = =m1/m2

Physics help
ma=F-F(fr) a=[F-F(fr)]/m s=at²/2

Physics
ω₀=2πn₀=2π/33.2=0.19 rad/s centripetal acceleration is a(cen) = ω₀²R=0.19²•42.2=1.52 m/s² tangential acceleration is a(tan) =ε•R =0.0542•42.2=0.12 m/s² acceleration is a=sqrt{ a(cen)²+a(tan)...

Physics
Man: φ =ω•t Dog: φ –π/2=ε•t²/2 ω•t= ε•t²/2 +π/2 ε•t² -2 ω•t+π=0 t={2±sqrt(4-2•3.14•0.31}/2•0.31 t1=3.74 s, t2 = 1.48 s ω(dog) = ε•t=0.3...

Physics
Man: φ=ω•t Dog: φ=ε•t²/2 ω•t= ε•t²/2 t=2 ω/ ε=2•0.5/0.31 =3.23 s ω(dog) = ε•t=0.31•3.23= 1 rad/s

Physics- PLEASE HELP
R=4.3 m, a(τ)=8.8 m/s². a(τ)=a(c) =v²/R => v=sqrt{a(c) •R}= sqrt{a(τ) •R}= =sqrt{8.8•4.3}=6.15 m/s. v=a(τ) •t, t= v/a(τ)=6.15/8.8 =0.699 s= 0.7 s. s= a(τ) •t²/2 =8.8•0.7²/2=2.156 m.

Physics
-0.33

Physics
13.3 cm

Physics
angle of incidence = 30o angle of reflection = 60o angle between incident ray and reflected ray = 120o

physics
α=arctan(Fy/Fx)=arctan(60/40)=arctan 1.5=56.3°

Physics
y: mg=T+N x: F(fr)=T N=mg-T F(fr)= μN=μ(mg- T) = μmg-μT =T T(1+μ)= μmg T= μmg/(1+μ)=0.49•710/1.49=233.5 Newtons

Physics
2•T•sinφ=2•19.5•sin16º=10.75 N

Physics!
F(x) =F1(x) +F2(x) F(x)= 57•cos30°+57•cos60° = F(y) =F1(y) +F2(y) F(y) =57•sin30°+57•sin 60° = F=sqrt{F(x)²+F(y)²} tan θ=F(y)/F(x) F(x) =F1(x) +F2(x) +F3(x) =0 57•cos30°+57•cos60° +F3(x) =0 F(y) =F1(y) +F2(y...

Physics
Initial heights of the blocks: m1 -> H; m2 -> h Initial energy of the “two blocks” system is E1 = m1•g•H+m2•g•h When the blocks covered s=0.9 m the energy of ”two blocks+spring” system is E2= m1•g(H-s•sinα) +m1•...

Physics
0.73 Tesla

Physics
Electrons are emitted with more velocity.

Physics
The atomic number increases by one.

Physics
Both the number of emission of electrons and the maximum velocity will increase.

Physics
1.103 m

Physics URGENT! PLEASE
ΣF(x) =F1(x) +F2(x) +F3(x) =0 0+42•cos60°+F3(x) =0 F3(x) = -42•cos60°= -21 N ΣF(y) =F1(y) +F2(y) +F3(y) =0 36+42•sin60°+F3(y) =0 F3(y) =-36 -42•sin60°= -72.4 N F=sqrt{F(x)²+F(y)²} tan θ=F(y)/F(x)

Physics
F=mv²/R m=FR/ v²

Physics
(m1+m2)a=F m1+m2 =F/a m2=F/a – m1

physics
change of current

physics
h=g•t²/2 t=sqrt(2•h/g) S=v(x) •t

physics
KE=W(fr) KE = m•v²/2 W(fr) =F(fr) •s m•v²/2 =F(fr) •s F(fr)= m•v²/2•s

physics
m1=130/9.8 kg , m2=63/9.8 = m1•a=0=T-F(fr) m2•a=0= m2g-T => T=m2•g F(fr) =T =m2•g

Physics
v=2πR/t = … a= a(n) =mv²/R F=ma

High School Physics
L=vₒ²•sin2α/g, sin2α=L•g/ vₒ²=126•32.174/98²=0.42 1) 2α=25° , α=12.5° 2) 2α =25+90=115°,, α=57.5° t= 2vₒ•sinα/g=...

Physics
m₀=ρV=ρ•πD³/6 ρ =920 kg/m³, D=0.021 m

Physics
mgh =mv²/2 v²= 2gh) = 2•9.8•10 =196 m²/s² a=v²/2•s =196/2•2.7=36.3 m/s² F(fr) = ma=69•36.3 =2504.7 N

physics
KE=PE KE=mgh h=KE/mg =50/0.55•9.8 =9.28 m

Physics- Projectiles
h= vₒ²•sin²α/2g,

physics college
Forward force = T•cosα

physics
Units????

Physics
m1•g=N+T m2•g=T m1•g=N+ m2•g N=(m1-m2)g

Physics
PE=KE + W(fr) mgh =mv²/2 + F(fr)•s m•g•s•sinα =mv²/2 +μ•m•g•cosα•s Solve for μ

Physics
m1 =4.3•10^-3 kg, m2 = 22.6•10^-3 kg, h =1.4 m, L= 3.1 m., v1 =? m1 •v1 = (m1+m2) •v, v= m1 •v1 /(m1 + m2) . h =g•t²/2 => t = sqrt(2•h/g) L= v•t = v• sqrt(2•h/g), v =L/sqrt(2•h/g), m1 •v1 /(m1 + m2) = L/sqrt(2...

Physics HELP!!
F(x) =F1(x)+F2(x)+F3(x) =0+19.9 +0 =19.9 N F(y) =F1(y)+F2(y)+F3(y) =11.1+0-14=-3 N F=sqrt{F(x)^2 + F(y)^2} a=F/m tan alpha=F(y)/F(x) unknown angle =appha +90 degrees

Physics HELP!!
(a) ma=F1-F2 F2=F1-ma (b)F2=F1 (c) -ma=F1-F2 F2=F1+ma

Physics
You accidentally got the right answer. Correect solution is following: The Earth makes one revolution (2π) during 1 year => the angular displacement for 5 days is θ= 2π•5/365 = 0.086 rad. The angular velocity of the Earth is ω= θ/t = 0.086/5...

Physics
If your question is: If a rod is moving at a velocity equal to 1/2 the speed of light parallel to its length, what will a stationary observer observe about its length? The answer is L=L₀•sqrt{1-(v/c)²}=0.866L₀ The length of the rod will decrease.

Physics
F=ILBsinα sinα=1 B=F/IL = 2.2/2•1.5 =0.73 T

Physics
Electrons are emitted with more velocity. ε(energy of photon) = Work function + KE ε(blue)>ε(green) => KE(blue) >KE(green) => v(blue) > v(green)

Physics
The atomic number increases by one.

Physics
The atomic number increases by one.

Physics
Both the number of emission of electrons and the maximum velocity will increase

physics
(a) sin r = sini/n =sin 58°/1.6=0.53 r =32 ° α=180°-58°-32°=90° (b) δ= 58 -32 =26°

Physics
Q(t)=Q₀•exp(-t/RC) E~Q² => E=E₀•exp(-2•t/RC) 100-80=20% 0.2•E₀=E₀•exp(-2•t/R•C) ln0.2 =- 2•t/R•C t= - ln0.2• R•C/2 =- (-1.6) •60•90•10⁻⁶/2 =0.0043 s.

texas southern university
p1•V1=p2•V2 p2=p1•V1/V2

texas southern university
T=1/f

physics/light reflection
(a) sin r = sini/n =sin 58°/1.6=0.53 r =32 ° α=180°-58°-32°=90° (b) δ= 58 -32 =26°

physics
Find the solution in Related Questions

physics
m1=1.7 kg, m2 =2.4 kg, L=1.29 m. PE=KE m1•g•L=m1•v²/2 v=sqrt(2•g•L) The velocities of the bodies after elastic collision are u1=(m1-m2)v/(m1+m2), u2=2m1v1/(m1+m2) “-“ means the motion in opposite direction

PHYSICS H
http://www.physicsclassroom.com/mmedia/newtlaws/efar.cfm

Physics
v=sqrt(2gh)

Physics
units???

physicsssss
ω=sqrt(k/m) = sqrt(160/0.885) =13.45 rad/s x=A•sinωt v=A•ω•cosωt v(max) = A•ω A= v(max)/ω =0.38/13.45 =0.028 m a= - A•ω²•sinωt a(max)= A•ω²=0.028•13.45²=5.065 m/s²

physics
k=mg/x=0.625•9.8/0.16 =38.3 N/m T=2•π•sqrt(m/k) m= k•T²/4π²

Physics
v(max) = A•ω ω = v(max)/A T=2π/ω k=mg/A

Physics
y(max1) =mλL/d λ=y(max1)•d/m•L tanα=y(max1)/L λ=tanα•d/m=tan2.5°•20•10⁻⁶/1=0.873•10⁻⁶ m tanα=L •m/d=….

Physics
Frequency is inversely proportional to wavelength. Wavelength is directly proportional to speed. λ=c/f

Physics
f=c/λ=3•10⁸/10⁻⁸ =3Hz

Physics
f=c/λ=3•10⁸/10⁸ =3Hz

Physics
λ=c/f=3•10⁸/6•10¹⁴=

Physics
ultra violet region

Physics
ℰ(max) =NBAω =30•0.04•0.25•100 = 30

Physics
L=L₀•sqrt{1-(v/c)²}=0.866L₀ The length of the rod will decrease.

Physics
Jenifer is right 1/F = 1/0.2 – 1/0.125 – 1/0.4 +1/0.1429 = =5-8-2.5+7 = +1.5 F= + 0.667 m

Physics
Lens 1- F'= +200mm=+0.2 m Lens 2- F'= -125mm = - 0.125 m Lens 3- F'= -400mm =- 0.4 m Lens 4- F'= +142.9mm= +0.1429 m 1/F = 1/0.2 – 1/0.125 – 1/0.4 +1/0.1429 = =5-8-2.5+7 = -3.5 F= - 0.286 m

Physics
C=Q/(T2-T1) c=Q/m(T2-T1)

physics to be conceptualize
In an isolated system where only conservative forces cause energy changes, the kinetic energy and potential energy of the system can change, but the mechanical energy of the system cannot change. The work done by a conservative force on a particle moving between two points mus...

Physics helppp
An isolated system is one in which objects inside the system are not influenced by any forces from outside the system.

Physics Please help !!
ΔU = U(x) - U(0) = ∫(6x - 12)dx Therefore, with U(0) = 23 J, we obtain by integrating U = 23 + 12x - 3x ² F = 0 when 6x - 12 = 0 Thus x = 2 m Substituting into U = 23 + 12x² - 3x , U = 35 J Using the quadratic equation find the negative and positive values...

physics
55 µm =55•10⁻⁶ m=0.000055 m=5.5 •10⁻⁷ m

physics
10.1 nm =0.0000000101=1.01•10⁻⁸ m= =1.01•10⁻ ⁵mm=1.01•10⁻ ²µm

physics
2. x = v t

Physics
F=qvBsinα sinα=1 => F=qvB F(p)=e2vB F(e) =evB F(p)/F(e) =2 ...2:1

Physics
m1+m2+m3 = 92.5 kg. m1= 0.31 kg m2+m3 =92.19 kg v=0.55 m/s v1= - 17 m/s v2=? (m1+m2+m3) •v= - m1•v1+(m2+m3) •v2 v2= {(m1+m2+m3) •v +m1•v1}/(m2+m3)=…

Physics
3/sqrt2 = 2.1 A

physics
r(x)= 13.8•cos15.5◦ r(x)= 13.8•sin15.5◦

Physics
Change of the horizontal component of the stone’s linear momentum is Δp(x) = m•v(0x) – (-mv(1x)} = m{v(ox)+v(1x)} = m{v(0) •cos15 +v1•cos12} For the boat Δp=p2-p1 = M•u – 0 = M•u. Thje law of conservation of linear momentum ...

physics
h=v²/2g

PHYSICS
m•g=k•x₁ k= m•g/x₁=0.116•9.8/0.035= 32.5 N/m When the spring rises 5.7 cm =0.057 m and the spring is compressed to x₂=0.022 m F= k•x₂ =ma a =k•x₂ /m=32.5•0.022/0.116 =6.16 m/s²

Physics
The rope it attached to the man’s hands, and the chair he is in. So, there are two tensions pulling upward on the “child-chair” system. m=(287+223)/g=510/g, T=265 N 2T=mg +ma ma= (2T-mg)/m = =g (2•265- 510)/510= =9.8(530-510)/510= =0.38 m/s² N=...

physics help i still dont get it
sinα =2,5/sqrt{2.5²+(43/2)²} =0.116 m•g=2•T•sinα T=m•g/2•sinα =52/2•0.116 =225 N

physics help i still dont get it
sinα =2,5/sqrt{2.5²+(43/2)²} m•g=2•T•sinα T=m•g/2•sinα

physics
F(net)=sqrt(F1²+F2²) a=F(net)/m

physics
m=1500/9.8 kg F=ma =0.8•1500/9.8= …(N)

Physics
(a) v₂= 2m₁v₁₀/(m₁+m₂) =2•5.9•27.6/(5.9+17.7)=13.8 cm/s (b) KE1(fin) –KE1(init) =m₁ •v₁₀²/2 –m₁•v₁²/2=0.5•m₁ (v₁₀² –v₁²)= =0.5&...

Physics
Number of turns in the primary coil is more than the number of turns in the secondary coil.

physics
m•g=k•x₁ k= m•g/x₁=0.116•9.8/0.035= 32.5 N/m When the spring rises 5.7 cm =0.057 m and the spring is compressed to x₂=0.022 m F= k•x₂ =ma a =k•x₂ /m=32.5•0.022/0.116 =6.16 m/s²

Physics
I1=U/R1=6.3 =2 A

physics need help bad
Find the answer in the Related Questions

Physics
The rope it attached to the man’s hands, and the chair he is in. So, there are two tensions pulling upward on the “child-chair” system. m=(287+223)/g=510/g, T=265 N 2Tmg ma ma= ( 2T-mg)/m = =g (2•265- 510)/510= =9.8(5...

Physics
1/R(eq)=3/R R(eq)=R/3

Physics
m1•v= (m1+m2) •u u = m1•v/ (m1+m2)

physics
(a) KE= KE(transl) +KE(rot) = m•v²/2+Iω²/2= = m•v²/2+ (2mR²)• v²/5•2•R²= = m•v²/2+ mv²/5 =0.7 mv² (b) KE=PE 0.7•m•v²=mgh h= 0.7•v²/g =…

Physics
(a) L1 = M•v•R = Earth’s mass is M = 5.97•10^24 kg, R= 1.5•10^11 m (Earth-Sun) v=ω•R=2•π•n•R n=1 rev/year =1/365•24•3600 rev/s L1 = M•v•R = M•2πn•R²= …(kg•m²/s) (b) Ea...

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