# Posts by Elena

Total # Posts: 4,389

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 ...

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

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

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(...

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) ...

Physics
ma= mg - N N=mg -ma

Physics
ma=-mg+N N=ma+mg

physics
v=v₀-at a= (v₀-v)/t s=v₀t -at²/2

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
ΔE=0.17 J, h=L(1-cosα) PE=KE+ΔE mgh=mv²/2 + ΔE mv² =2{mgL(1-cosα)- ΔE} T= mv²/L + mg = 2{mgL(1-cosα)- ΔE}/L +mg

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
(a)ma=F-F(fr) F(fr)= F-ma (b) F(fr) =μmg μ=F(fr)/mg

Physics
m=F/a

Physics
F(y) =Fsinα

Physics
g(Moon) =g1=1.63N/kg. m=W1/g1=2000/1.63=1227 kg W(Earth)=W2=mg=1227•9.8=12025 N

physics
v=v₀+at v₀=0 v=at a=v/t s=at²/2

physics
ma=F(fr) =μmg a= μ•g v=v₀-at

physics
1. N1=(m(per) +m(cr))g 2. N2=m(per)g

Physics
zero V/m

Physics
Ñ=q/V= 3.3x10^-6 F

Physics
(a) Torque1= W•L•sinα = 12000•2.5•sin32°=… (b) Torque2=T•L•cosα=54200•2.5•cos32°=…

physics
T1= 101◦F =311.48K T2= 70°F=294.26 K Since the emissivity is 1, the object is the black body => P=R•A= σ•T⁴•A ΔP= σ•T1⁴•A - σ•T2⁴•A = σ•A•( T1⁴ - T2⁴)= =5.67•...

Physics
n=33rpm=33/60 =0.55rev/sec ω =2πn=2π•0.55=3.45 rad/s The rod is rotating clockwise about ITS CENTER OF MASS. The center of mass is at r=4.63/2 =2.315 m from each end of the rod.Then M=Iε =(m1•r²+m2•r²)•ω/t = r²(m1+m2...

physics
1. N1=(m(per) +m(cr))g 2. N2=m(per)g

physics
c. takes a short time to cool off.

Physics
Work=P •m•t= P•m•s/v= =6.5•75•145000/13.5=5.23•10⁶J = = 1.25•10³ nutr.Cal. Now it's OK

Physics
Work=P •m•t= P•m•s/v =6.5•75•145000/13.5=5.23•10⁶J =1.25 nutr.Cal.

Physics
Work= •m•t= P•m•s/v =6.5•75•145000/13.5=5.23•10⁶J =1.25 nutr.Cal.

Physics
Power is the rate of energy (here, kinetic energy) => P=W/t= mv²/2t = 114•18.2²/2•2.7 = 6993 W = =9.37 hp 1 hp = 745.66272 W

Physics
m•v²/2=mgh=m•g•s•sinα v=sqrt(2• g•s•sinα)

Physics
m•v1²/R1=T1 m•v2²/R2=T2=4•T1 v2²=4•v1²•R2/R1 W=KE2-KE1 = m•v1²/2 - m•v2²/2 = = m•v1²/2- m• 4•v1²•R2/2•R1 = = m•v1² { 1- (2•R2/R1)}/2= = 0.82•21²{1-(2&#...

physics
KE=PE 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 0.7•m•v²=mgh v=sqrt(g•h/0.7)

Physics
Guitar pickups are tiny coils with magnets inside them. The magnets magnetize the steel strings. When the strings vibrate, voltage is induced in the coils and boosted by an amplifier, and sound is produced by a speaker.

Physics
2Tsinα=mg T=mg/2sinα

Physics
t=s/{v(plane)-v(wind} !!! km/h -> m/s

Physics
T=mgsinα

Physics
F=2•F(fr)+mg =2•μ•N +mg N=(F+mg)/2• μ

Physics
Figure???

Physics
h = v²/2g

physics
γ= 2.675•10⁸ T⁻¹•s⁻¹ γ/2π =42.58 MHz/T f= γ•B = 2.675•10⁸•3 = 8.0250•10⁸s⁻¹ B1=3 + 3•10 ⁻⁵•10=3+3•10⁻⁴ T=3.0003 T f1= γ•B1 = 2....

physics
v=5.2/tan30 = 9m/s

Physics
h=v²/2g=5.6²/2•9.8 =1.6m. Upward motion W1=-mgh= - 0.135•9.8•1.6= - 2.12 J Downward motion W2= mg(H+h) = 0.135•9.8•(1.94+1.6) =4.68 J W= W1+W2 = -2.12 +4.68 = 2.56 J.

physics
F(fr)=mv²/R

physics is annoying
ΣFx= -F(A) •cos47 +F(C)cosφ=0 ΣFy= F(A) •sin47 +F(C) sinφ –F(B) =0 -227•0.68 +175•cosφ=0 227•0.73 +175•sinφ –F(B) = 0 154.36 =175•cosφ cosφ=154.36/175 = 0.88 φ= 28.36° sin28.36°=0...

physics to be solved ..easy !!
Misprint Vy•t - a•t²/2 = 2.11. The solution is correct. Check my calculations

physics to be solved ..easy !!
Vx•t = 15.1 V•cos(33.8) •t = 15.1 t=15.1/(V•cos33.8) (1) Vy•t+ a•t²/2 = 2.11 V•sin(33.8)•t - 0.5•(9.8)•t²= -2.11 (2) Plugging (1) into(2) V•sin(33.2)( 15.1/(V•cos33.8) - 4.9•{15.1/(V•cos33.8) }2...

physics help needed very urgent !!!
m1 = 10.5 kg, m3 = 14.7 kg, m4 = 22.05 kg, T2 = 120 N, and T4 = 236 N. m2=? (m1+m2+m3+m4)a=T4 (m3+m4)a=T4-T2 (10.5+m2+14.7+22.05)a =236 (14.7+22.05)a=236-120 a=116/36.75 =3.16 m/s² (10.5+m2+14.7+22.05)a =236 m2={236-(10.5+14.7+22.05)3.16}/3.16 = 27.43 kg

Physics
ma=μmg a=μg v=v₀-at,

Physics URGENT!!!
Please see the Related Questions below

Physics
E = v / d

Physics
N=q/e =6•10⁻⁶/1.6•10⁻¹⁹=3.75•10¹³=4•10¹³

physics
s=s1+s2+s3 =20•2+40•2+60•6 =480 m t=t1+t2+t3 =2+2+6 =10s v(ave) =s/t =480/10=48 m/s ---D

physics
F1+F2=F(fr)=μ•m•g μ=(F1+F2)/m•g

Physics
Value of the force is decreased by four. F=k•q1•q2/r² If r2=2•r1, F2=F1/4

Physics
F=qvBsinα If sinα=0 F=0

colledge physics
Question???????

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