Tuesday

September 1, 2015
Total # Posts: 10,938

**Physics**

Series Connection: When one lamp burns out, all of the lamps go out. So you are in the dark until the lamp is replaced.
*February 8, 2015*

**physics**

7grams * 5.66*10^21atoms/gram * 46e/atom = 1.82252*10^24 Electrons. b. 1.82252*10^24e * 1.6*10^-19C/e = 2.916*10^5 C. = Your answer.
*February 8, 2015*

**physics**

1/f = 1/di + 1/do LCD = di*do 1/f = do/di*do + di/di*do 1/f = (do+di)/di*do Invert both sides: f = di*do/(do+di)
*February 8, 2015*

**physics**

KE = KE1 + KE2 = 0.5*M*V^2 + KE2 = 0.5*0.6*3^2 + 2.5 = 5.2 J. KE = 0.5*0.6*V^2 = 5.2 V^2 = 17.33 V = 4.16 m/s.
*February 8, 2015*

**physics**

a = (V-Vo)/t = (9.3-0)/1.39 = 6.69 rad/s^2
*February 8, 2015*

**science**

P = F * d/s = Mg * d/t = 5000 * 25/50 = 2500 J./s = 2500 W.
*February 8, 2015*

**physics**

a. KE = 0.5*M*V^2 = 0.5*66*4.3^2 = 610.2 J. = Energy lost due to friction. b. M*g = 66 * 9.8 = 646.8 N. = Wt. of runner = Normal(Fn). Fk = u*Fn = 0.6 * 646.8 = 388.1 N. = Force of kinetic friction. KE = Fk*d = 610.2 388.1*d = 610.2 d = 1.57 m.
*February 8, 2015*

**physics**

Vo = 111km/h = 111000m/3600s. = 30.8m/s W = KE = 0.5M*Vo^2 =
*February 7, 2015*

**Physics**

2.76km[0o] + 0.85km[270o] X = 2.76*Coso + 0.85*cos270 = 2.76 N. Y = 2.76*sin0 + 0.85*sin270 = Fr = sqrt(X^2+Y^2)
*February 7, 2015*

**Physics**

24N[60o] + 9N[0o] X = 24*Cos60 + 9*Cos0 = 21 N. Y = 24*sin60 + 9*sin0 = 20.8 N. Fr^2 = 21^2 + 20.9^2 = 873.64 Fr = 29.6 N.
*February 7, 2015*

**Physics**

Pellet A: V = Vo + g*Tr Tr = -Vo/g = -27.3/-9.8 = 2.79 s. = Rise time. Tf1 = Tr = 2.79 s. = Time to Fall back to the edge of the cliff. Tf2 = Fall time from edge of cliff to gnd. Ta = Tr + Tf1 + Tf2 = 2.79 + 2.79 + Tf2 = 5.57 + Tf2. = Time in air, pellet A Pellet B: Tb = Tf = ...
*February 7, 2015*

**Physics**

Vo = 17.6m/s[29o] Xo = 17.6*Cos29 = 15.4 m/s Yo = 17.6*sin29 = 8.53 m/s Y = Yo + g*Tr = 0 Tr = -Yo/g = -8.53/-9.8 = 0.870 s. = Rise time. Range = Dx = Vo^2*sin(2A)/g = 17.6^2*sin(58)/9.8 = 26.8 m. h = Yo*Tr + 0.5g*Tr^2 = 8.53*0.870 - 4.9*0.870^2 = 3.71 m. = Max. ht. Xo*(Tr+Tf...
*February 6, 2015*

**Physics**

Vo = 16.0m/s[51o] Yo = 16*sin51 = 12.43 m/s. = Vertical component of initial velocity. Y = Yo + g*Tr = 0 Tr = -Yo/g = -12.43/-9.81 = 1.27 s. = Rise time. h = Yo*Tr + 0.5g*Tr^2 = 12.43*1.27 - 4.9*1.27^2 = 7.89 m. = Max. ht. h = ho - 0.5g*Tf^2 = 2 m 7.89 - 4.9*Tf^2 = 2 4.9Tf^2...
*February 6, 2015*

**physics**

R = E/I = 2.60/0.665 = 3.91 Ohms = Total resistance. Rl = 3.91 - 0.182-0.139 = 3.589 Ohms = Lamp resistance.
*February 6, 2015*

**physics**

See Related Questions: Thu, 9-12-13, 6:35 PM.
*February 6, 2015*

**physic**

See previous post: Sun, 2-8-15, 7:40 PM.
*February 5, 2015*

**Physics**

P = 0.5M*V^2/t = 0.5*65*12^2/3 = 1560 J/s = 1560 Watts
*February 5, 2015*

**PHYSICS**

a. d = Vo*t = 60 m 26 * t = 60 t = 2.31 s. = Fall time. h = 0.5g*t^2 = 4.9*2.31^2 = 26.1 m. b. h = Same as part a.
*February 5, 2015*

**physic**

A. M1*V1 + M2*V2 = M1*V3 + M2*V4 0.25*0+0.20*2.20=0.25*V3 + 0.20*1.5[37] 0.44 = 0.25V3 + 0.3[37o] 0.44 = 0.25V3 + 0.3*Cos37 + i0.3*sin37 0.44 = 0.25V3 + 0.240 + 0.181i -0.25V3 = 0.240 - 0.44 + 0.181i = -0.25V3 = -0.20 + 0.181i V3 = 0.8 - 0.734i V3 = sqrt(0.8^2+0.734^2) = 1.18 ...
*February 5, 2015*

**physics**

h = 0.5g*t^2 = 100-25 4.9*t^2 = 75 t^2 = 15.31 t = 3.91 s. = Fall time. Dx = Xo*t = 20 m. Xo*3.91 = 20 Xo = 5.11 m/s. = Hor. velocity.
*February 5, 2015*

**physical**

Fr^2 = F1^2+F2^2
*February 5, 2015*

**physics**

See Related Questions: Sun, 10-21-13, 9:10 PM.
*February 4, 2015*

**physics**

V-Vo = 6.24/m/s[-54.3o]-5.45m/s[38.5o] X = 6.24*Cos(-54.3) - 5.45*Cos38.5 = -0.624 m/s Y = 6.24*sin(-54.3) - 5.45*sin38.5 = -8.46 m/s ax = -0.624/4.0 = -0.156 m/s^2 ay = -8.46/4.0 = -2.115 m/s^2
*February 4, 2015*

**physics**

F = m*a = 7000kg * 9.8N/kg = 68,600 N. W = F*d
*February 4, 2015*

**trig**

067degree
*February 4, 2015*

**Math**

Ax + By + C = 0
*February 4, 2015*

**physics**

R = 650 + 350 + 1000 =
*February 4, 2015*

**math**

a. P = 9/(10+9+6) = 9/25. green P = 6/(10+8+6) = 6/24 = 1/4. blue.
*February 4, 2015*

**physics**

a. V^2 = Vo^2 + 2a*d V = 0 Vo = 16 m/s d = 10 m. Solve for a. b. V = Vo + a*t V = 0 Vo = 16 m/s. a = Value calculated in part a. Solve for t.
*February 3, 2015*

**physics**

X = -3.5 + 0 + 5.5 = 2.0 Y = 4.5 -6.5 -2.5 = -4.5 Tan A = Y/X = -4.5/2 = -2.250 A = -66.0 CW = 294o CCW.
*February 3, 2015*

**algebra**

x = -6 x+6 = 0 x = -4 x+4 = 0 Y = (x+6)(x+4) = 0 Y = x^2 + 4x + 6x + 24 = 0 Y = x^2 + 10x + 24 = 0
*February 3, 2015*

**math**

See previous post: Tue, 2-3-15, 7:55 PM.
*February 3, 2015*

**business calc**

30yrs * 12mo/yr. = 360 Mo. P = 450.23/mo. * 360mo. = 162,082.80 Cost = P-Po = 162,082.80 - 52,000 = 110,082.80
*February 3, 2015*

**Math**

Vo = 5*0^2 - 12*0 + 7 = 7 m/s. t = 0. V = 5*2^2 - 12*2 * 7 = 3 m/s. t = 2 s. a = (V-Vo)/t = (3-7)/2 = -2 m/s^2.
*February 3, 2015*

**math**

Circumference = pi*Dia. = 3.14 * 27 = 84.823 in = 7.07 Ft. 1 Mile = 5,280 Ft. 5,280Ft. * 6.28rad/7.07Ft. = 4,690 Rad.
*February 3, 2015*

**math**

h = ho + ho*0.15*10 = 27 in. ho + 1.5ho = 27 2.5ho = 27 ho = 10.8 In. = Initial ht. h = 10.8 + 10.8*0.15*9 = 25.4 Inches yesterday.
*February 3, 2015*

**Math**

Multiply Eq1 by 3 and add: 12x-6y = 21 3x+6y = 9 Sum:15x = 30 X = 2 In Eq2, replace x with 2: 3*2 + 6y = 9 6 + 6y = 9 6y = 9 - 6 = 3 Y = 1/2.
*February 3, 2015*

**Math**

P = X + 1.3X P = 2.3X
*February 3, 2015*

**algebra**

Correct!
*February 3, 2015*

**Math**

The slopes of perpendicular lines are negative reciprocal of each other. a. m1 = (1-4)/(-1-1) = -3/-2 = 3/2 b. m2 = (-1-3)/(-1-3) = -4/-2 = 2 The 2 lines are not perpendicular. Note: If the slope of the 2nd line was -(2/3), the lines would be perpendicular.
*February 3, 2015*

**physics**

T1*sin(90+45) + T2*sin45 = 40. 0.707T1 + 0.707T2 = 40. T1 = T2. Replace T2 with T1: 0.707T1 + 0.707T1 = 40. T1 = 28.3 N. = T2.
*February 3, 2015*

**math**

What are the critical values on the graph of y = x^3 - 6x^2 + 9x + 3?
*February 3, 2015*

**physics**

0.200 kg block: d = 0.5a*t^2 = 0.44 m. 0.5a*2^2 = 0.44 2a = 0.44 a = 0.22 m/s^2. 0.400 kg block: d = 0.5a*t^2 = 0.5 * 0.22*2^2 = 0.44 m
*February 2, 2015*

**Physics**

Jack: V = d/t = 9*25m/160.1s. = Ans. in m/s. Jill: V = d/t = 10*25m/160.1s = Ans. in m/s.
*February 2, 2015*

**physics**

W = F*d = 34.5*10^6 * 393*10^3 = Answer in Joules.
*February 2, 2015*

**Physics**

V = Vo + g*Tr = 0 7.65 - 9.81*Tr = 0 9.81Tr = 7.65 Tr = 0.780 s. = Rise time. h = ho + Vo*Tr + 0.5g*Tr^2 h = 12.7 + 7.65*0.78 - 4.9*0.78^2 = 15.69 m. Above gnd. a. V^2 = Vo^2 + 2g*h = 0 + 19.6*15.69 = 307.4 V = 17.53 m/s b. h = 0.5g*t^2 = 15.69 4.9t^2 = 15.69 t^2 = 3.20 t = 1....
*February 2, 2015*

**Physics**

Vo = 8.50m/s[-23o] Xo = 8.50*Cos(-23) = 7.82 m/s. Yo = 8.50*sin(-23) = -3.32 m/s. = Ver. component of initial velocity.
*February 2, 2015*

**Physics**

P = Es*Is = 150,000 Watts 120*Is = 150,000 Is = 1250 Amps. = Current flowing through secondary coils. Ip = 140/25000 * 1250 = 7 Amps = current through primary coils and transmission lines.
*February 2, 2015*

**Physics**

M1*V1 + M2*V2 = M1*V3 + M2*V4 0.045*134 + 1.5*0 = 0.045*78 + 1.5*V4 Solve for V4.
*February 2, 2015*

**Physics**

Conservation of momentum: Total momentum before the collision = Total momentum after the collision. M1*V1+M2*V2 = M1*V+M2*V = (M1+M2)*V 46*529 + 1000*0 = 1046*V Solve for V.
*February 2, 2015*

**Physics**

a = (V-Vo)/t V = 16.7 m/s Vo = 10.3 m/s. M = F/a
*February 2, 2015*

**physics**

1. Fx = 20*cos30 = 17.32 N. 2. Work = Fx*d = 0 * 10 = 0 3. a. 4. W = Fx*d = 255*Cos60 * 15 = 5.
*February 2, 2015*

**Physical Science**

Scale1 = x Newton. Scale2 = 2x Newton x + 2x = 1200 N. Solve for x.
*February 2, 2015*

**Physics**

See Related Questions: Fri, 1-31-14, 10:23 PM.
*February 2, 2015*

**Physics**

Vo = 31.1m/s[37o] Xo = 31.1*Cos37 = 24.84 m/s. Yo = 31.1*sin37 = 18.72 m/s. Y = Yo + g*Tr = 0 18.72 - 9.8*Tr = 0 9.8Tr = 18.72 Tr = 1.91 s. = Rise time. Y^2 = Yo^2 + 2g*h = 0 h=-Yo^2/2g = -(18.72)^2/-19.6 = 17.88 m = Max. ht. 0.5g*t^2 = 17.88 - 5.50 4.9t^2 = 12.38 t^2 = 2.53 t...
*February 2, 2015*

**Science**

Fs = u*Fn = 0.4 * 20 = 8 N.
*February 2, 2015*

**Physics**

M*g = 150 N. g = 1.63 m/s^2 Solve for M(kg).
*February 2, 2015*

**science**

h = o.5g*t^2 h = 10 m. g = +9.8 m/s^2 Solve for t.
*February 2, 2015*

**physics**

Please disregard my 5:24 PM post.
*February 2, 2015*

**physics**

Tr = 1.5 + 1 = 2.5 s. = Rise time or time to reach max ht. V = Vo + g*Tr = 0 Vo -9.8*2.5 = 0 Vo = 24.5 m/s. = Initial velocity. h = Vo*t + 0.5g*t^2 = 24.5*1.5 - 4.9*1.5^2 = 25.7 m. = Ht. of the tower.
*February 2, 2015*

**physics**

Tr = 1.5 + 1 = 2.5 s. = Rise time or time to reach max ht. V = Vo + g*Tr = 0 Vo -9.8*2.5 = 0 Vo = 24.5 m/s. = Initial velocity. h max = Vo*t + 0.5g*t^2 = Vo*2.5 - 4.9*2.5^2 = 2.5Vo -
*February 2, 2015*

**physics**

d = 3.70 m. h = 1.67 m. V^2 = Vo^2 + 2g*h = 0 + 19.6*1.67 = 32.73 V = 5.72 m/s. = Velocity at bottom of incline. d = 0.5g*t^2 = 1.67 m. 4.9t^2 = 1.67 t^2 = 0.341 t = 0.584 s. = Time to reach bottom. V = Vo + a*t a = (V-Vo)/t V = 5.72 m/s Vo = 0 Solve for a.
*February 1, 2015*

**Physics**

Not enough INFO.
*February 1, 2015*

**Physics**

See Related Questions: Fri, 1-31-14, 10:23 PM.
*February 1, 2015*

**physics**

Vo = 1520m/s[35.5o] Yo = 1520*sin35.5 = 883 m/s. KE = 0.5M*Yo^2 = 0.5*25*883^2 KE = 0.5M*Yo^2 = 0.5*25*883^2=9,746,113 J. PE = KE = Mg*h = 9,746,113 25+9.8*h = 9,746,113 245h = 9,746,113 h = 39,780 m.
*February 1, 2015*

**PYHSICS**

With Arrow A = 9i B = -4 a. A+B = 9i + (-4) Q2. A+B = sqrt(9^2+(-4^2) = 9.85 Units. Tan Theta = 9/-4 = -2.25 Theta = -66.0 + 180 = 114o, CCW(Q2). b. A-B = 9i - (-4) = 9i + 4 A-B = sqrt(9^2+4^2) = 9.85 Units. Tan Theta = 9/4 = 2.25 Theta = 66o c. B-A = -4 - 9i X = -4 Y = -9
*February 1, 2015*

**physics**

Fg = 440 Hz = Freq. of the generator. Vg = 40 m/s = Velocity of the generator. Vs = 343 m/s = Velocity of sound. Vr = 0 = Velocity of the receiver(person listening to the sound). Fr = ((Vs+Vr)/(Vs-Vg))*Fg Fr = ((343+0)/(343-40))*440 = (343/303)*440 = 498.1 Hz. = Freq. heard by...
*February 1, 2015*

**Physics**

Impulse = M*(V-Vo) = 1295*(-1.5-25) = 34,318 kg*m/s
*February 1, 2015*

**physics**

Correction: Impulse = M*(V-Vo) = 0.42*(-27-12) = -16.4 kg*m/s
*February 1, 2015*

**physics**

V = Vo + a*t = -27 m/s. 12 + a*0.016 = -27 0.016a = -27 - 12 = -39 a = -2438 m/s^2 Impulse = M*V = 0.42 * (-27) = -11.34 F = M*a = 0.42 * (-2438) = 1024 N.
*February 1, 2015*

**physics**

See previous post: Wed, 1-28-15, 6:19 PM.
*February 1, 2015*

**Chemistry**

The primary route for making copper iodide is by reacting potassium iodide with copper sulfate: 2CuSO4 + 4KI + 2Na2S2O3 ==> 2CuI + 2K2SO4 + 2NaI + Na2S4O6 Identify potential green chemistry and green engineering challenges of the reaction.
*February 1, 2015*

**Physics**

Dc = Dp 0.5a*t^2 = 8.93 * 2.88 0.5a*2.88^2 = 25.72 Solve for a.
*January 30, 2015*

**Physics**

V = 43.3 m/s. a = -5.61 m/s^2 d = 24 + 55.9 = 79.9 m. V^2 = Vo^2 + 2a*d = 43.3^2 Vo^2 - 11.22*79.9 = 1874.9 Vo^2 = 1874.9 + 21036 = 22,911 Vo = 151.4 m/s. = Initial velocity. V = Vo + a*t V = 43.3 m/s. Vo = 151.4 m/s. a = -5.61 m/s^2 Solve for t.
*January 30, 2015*

**Physics**

V^2 = Vo^2 + 2a*d V = 333 m/s. Vo = 370 m/s. d = 12 cm = 0.12 m. Solve for a. It will be negative.
*January 30, 2015*

**physics**

h = Vo*t + 0.5g*t^2 = 1.5 m. Vo*0.18 + 4.9*0.18^2 = 1.5 0.18Vo + 0.159 = 1.5 0.18Vo = 1.5 - 0.159 = 1.34 Vo = 7.45 m/s = Initial velocity at top of window. V^2 = Vo^2 + 2g*h = 7.45^2 0 + 19.6*h = 55.5 h = 2.83 m. Above the window.
*January 30, 2015*

**Green Chemistry**

The primary route for making copper iodide is by reacting potassium iodide with copper sulfate: 2CuSO4 + 4KI + 2Na2S2O3 ==> 2CuI + 2K2SO4 + 2NaI + Na2S4O6 Identify potential green chemistry and green engineering challenges of the reaction.
*January 30, 2015*

**physics**

V^2 = Vo^2 + 2a*d V = 0 Vo = 125 m/s a = -9.8 m/s^2 Solve for d, the length.
*January 30, 2015*

**physics**

0.5g*t^2 = 2 4.9t^2 = 2 t^2 = 0.408 Tf = 0.639 s. = Fall time. Tr = Tf = 0.639 s. = Rise time. Tr+Tf = 0.639 + 0.639 = 1.28 s. = Time in air.
*January 29, 2015*

**physics**

M*g = 74.6kg * 9.8N/kg = 731.1 N. = Wt. of the skier. Fp = 731.1*sin39.0 = 460.1 N. = Force parallel to the incline. Work = Fp*d = 460.1 * 63.3 = 29,124 J.
*January 29, 2015*

**Physic**

V^2 = Vo^2 + 2g*h V = 0 Vo = 78.5 m/s. g = -9.8 m/s^2. Solve for h.
*January 29, 2015*

**Physics**

Circumference = pi*Dia. = 3.14 * 50 = 157.1 cm. 25rad * 1rev/6.28rad = 3.98 revs. d = 157.1cm/rev * 3.98revs = 625.4 cm.
*January 29, 2015*

**Need Help Physics**

Vbc = Vb + Vc = 6.44i Vb + 1.09 = 6.44i Vb = -1.09 + 6.44i Tan Ar = Y/X = 6.44/-1.09 = -5.90826 Ar = -80.4o = Reference angle. A = -80.4 + 180 = 99.6o, CCW = 9.6o W. of N.
*January 29, 2015*

**Maths**

PQ = X1 = 15 m. X2 = hor. distance from Q to kite. Tan45 = h/X2 h = X2*Tan45 Tan35 = h/(X1+X2) h = (X1+X2)*Tan35 = (15+X2)*Tan35 X2*Tan45 = (15+X2)*Tan35 X2 = 10.5 + 0.7X2 0.3X2 = 10.5 X2 = 35 m. h = X2*Tan45 = 35 * Tan45 = 35 m. h = (X1+X2)*Tan35 = 50*Tan35 = 35 m.
*January 29, 2015*

**physics**

e. None of the above.
*January 29, 2015*

**physics**

d = Vo*t + (-Vo^2/2a) = 25*0.564 + -(25^2)/-8 = 92.2 m.
*January 29, 2015*

**physicss**

V = Vo + a*t = -52 m/s 44 + a*0.003 = -52 0.003a = -52 - 44 = -96 a = -0.032 m/s^2 F = M*a
*January 29, 2015*

**physics**

a. Vo = 25m/s[35o] Xo = 25*Cos35 = Yo = 25*sin35 = b. See previous prob. c. See previous prob.
*January 29, 2015*

**physics**

Vo = 20m/s[30o] Xo = 20*Cos30 = 17.3 m/s. Yo = 20*sin30 = 10 m/s. Y = Yo + g*Tr Y = 0 Yo = 10 m/s. g = -9.8 m/s^2 Solve for Tr(Rise time). Tf = Tr = Fall time. Dx = Xo * (Tr+Tf)
*January 29, 2015*

**physics**

h = 0.5g*t^2 h = 1.40 m g = +9.8 m/s^2 Solve for t(Fall time). Xo = 0.600 m/s Dx = Xo * t
*January 29, 2015*

**physics**

Mass = 5.0L * 1oz/0.03L * 0.454kg/16oz = 4.73 kg.
*January 28, 2015*

**Physics**

V = 115km/h = 115000m/3600s = 31.94 m/s. Momentum = m*V Direction: East.
*January 28, 2015*

**physics**

d = V*t = 8 miles (Vs-Vc)t = 8 Vs = 1.7 m/h Vc = 0.7 m/h Solve for t.
*January 28, 2015*

**physics**

V = Vo + a*t V = 0 Vo = 8.2 m/s t = 5.8 s. Solve for a (It will be negative). F = m*a
*January 28, 2015*

**Physics**

V^2 = Vo^2 + 2g*h V = 0 Vo = 78.5 m/s. g = -9.8m/s^2 Solve for h.
*January 27, 2015*

**Physics**

Vbw = Vb + Vw = 6.44i Vb + 1.09 = 6.44i Vb = -1.09 + 6.44i, Q2. Tan A = Vbw/Vw = 6.44//-1.09 = -5.90826 A = -80.4o = 80.4o N. of W. = 99.6o CCW = 9.6o W. of N. = The direction.
*January 27, 2015*

**Physics**

h = 15 m Xo = 478 m/s? = Initial hor. speed. h = 0.5g*t^2 = 15 m 4.9t^2 = 15 t^2 = 3.06 Tf = 1.75 s.Fall time. Dx = Xo*Tf = 478m/s * 1.75s = 836 m. From bottom of cliff.
*January 25, 2015*

**physics**

V = 11.5m/s[236o] - 6.7m/s[270o] V = 11.5*Cos236 + 11.5*sin236 - (-6.7i) = -6.43 - 9.53i + 6.7i = -6.43 - 2.83i Tan Ar = Y/X = -2.83/-6.43 = 0.44074 Ar = 23.8o = Reference angle. A = 23.8 + 180 = 203.8o, CCW = 66.2o W. of S. = Direction. V = X/Cos2o3.8 = -6.43/-.915 = 7.03 m/s...
*January 25, 2015*

**physics**

h = 0.5g*t^2 = 2 m. 4.9t^2 = 2 t^2 = 0.408 Tf = 0.639 s. = Fall time. Xo*Tf = 4.4 m Xo * 0.639 = 4.4 Xo = 6.89 m/s.
*January 25, 2015*

**phys**

V = Vo + g*t Vo = 0 g = +9.8 m/s^2 t = 3.5 s. Solve for V.
*January 25, 2015*