Friday

February 12, 2016
Total # Posts: 11,509

**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*

**physics**

F = 225N/m * 0.15m = 33.75 N.
*January 25, 2015*

**physics**

V^2 = Vo^2 + 2a*d = 15^2 37^2 + 2a*0.31 = 15^2 2a*0.31 = 15^2 - 37^2 a = (15^2-37^2)/0.62 = -1845.2 m/s^2 A. V = Vo + a*t t = (V-Vo)/a = (15-37)/-1845.2 = 0.012 s B. V^2 = Vo^2 + 2a*d V = 0 Vo = 37 m/s a = -1845.2 Solve for d(thickness).
*January 25, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*0.76 24*60.8 + 12*15.2 = 24*V + 12*0.76. Solve for V(cm/s).
*January 25, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*V 2100*12 + 2780*0 = 2100V + 2780V 25,200 = 4880V V = 5.16 m/s. See Related Questions: 10-30-14, 9:40 PM.
*January 25, 2015*

**Physics**

When they are acting in the same direction: 5 + 7 = 12 N.
*January 25, 2015*

**Physics**

V = 22.6km/18min * 1min/60s = 0.0209 km/s = 20.9 m/s.
*January 25, 2015*

**College Physics**

d = V*t = 0.12 m t = 0.12/V = 0.12/7*10^7=1.71*10^-5 s.
*January 24, 2015*

**Physics**

Dc = 19t = Distance of the car after t1. Dm = Vo*t + 0.5a*t^2 = Distance of motorcycle after t1. Dm = Dc + 52 Vo*t + 0.5a*t^2 = 19t + 52 19*t + 2.5*t^2 = 19t + 52 19t - 19t + 2.5*t^2 = 52 t^2 = 20.8 t = 4.56 s. So the motorcycle caught-up 4.56 s after it started to accelerate.
*January 24, 2015*

**Physics**

V1/V2 = M2/M1 = 56kg/96kg = 0.583
*January 24, 2015*

**science**

a. Fx = 3000*Cos30 = 2598 N. b. Fy = 3000*sin30 = 1500 N. = Lifting force.
*January 24, 2015*

**Physics**

See previous post: Fri, 1-23-15, 5:42 PM.
*January 24, 2015*

**Physics**

V^2 = Vo^2 + 2a*d = 0 Vo^2 = -2a*d = -2*(-7.2)*72 = 1036.8 Vo = 32.2 m/s. = Speed before braking.
*January 23, 2015*

**math**

Let g = 10 m/s^2. d = 0.5g*t^2 = 5*9^2 = 405 m.
*January 23, 2015*

**physics**

Vo = 50m/s @ A Degrees Xo = 50*Cos A Yo = 50*sin A Y^2 = Yo^2 + 2g*h = 0 @ max ht. Yo^2 = -2g*h = -2*(-9.8)*100 = 1960 Yo = 44.27 m/s = Ver. component of initial velocity. Yo = 50*sin A = 44.27 sin A = 44.27/50 = 0.88544 A = 62.3o. = Angle of projection. Y = Yo + g*Tr = 0 Tr...
*January 23, 2015*

**science**

d1 + d2 = 12 m. d1 = Vo*t + 0.5g*t^2 d2 = 0.5g*t^2 16*t - 4.9*t^2 + 4.9*t^2 = 12 16*t = 12 t = 0.75 s.
*January 22, 2015*

**science**

a = (V-Vo)/t = 30-0)/10 = 3 m/s^2
*January 22, 2015*

**Physics**

P = F * d/t = M*g * d/t = 5*9.8 * 12/15 = 39.2 J/s = 39.2 Watts.
*January 22, 2015*

**physics**

Vo[51o] Xo = 7 m/s Vo = ? Xo = Vo*Cos51 = 7 m/s Vo = 7/Cos51 = 11.12 m/s = Initial velocity. Yo = Vo*sin51 = 11.12*sin51 = 8.64 m/s.
*January 22, 2015*

**physics**

Increase = (26-(-16))C*1.7*10^-5/C*30cm = 42*1.7*10^-5 * 30cm =0.02142 cm.
*January 22, 2015*

**math**

1. (7a^5-a^3) - (a^5-5a^3-1) Remove the parenthesis: 7a^5-a^3 - a^5+5a^3+1 Combine like-terms: 6a^5 + 4a^3 + 1
*January 22, 2015*

**Math**

(3x+4)*Log2 4 = (3x+4)*2 = 6x + 8.
*January 22, 2015*

**math**

h(t) = -4t^2 + 30t + 1.4 Tr = -B/2A = -30/-8 = 3.75 s. = Rise time. Tf = Tr = 3.75 s. = Fall time. Tr+Tf = 3.75 + 3.75 = 7.5 s. To get under the ball.
*January 22, 2015*

**Math**

X Girls. (x+45) Boys. 2x/3 girls passed the test. (4/5)(x+5) = (4x/5 + 4) boys passed test 49 Children failed the test. (x - 2x/3) = x/3 = Girls that failed the test. (X+45) - (4x/5+4) = x/5+41 Boys that failed the test. X/3 + (x/5+41) = 49 x/3 + x/5 = 49-41 = 8 Multiply both ...
*January 22, 2015*

**physics**

Incomplete.
*January 22, 2015*

**phyisics**

h = 1*sin30 = = 0.5 m. V1^2 = Vo^2 + 2g*h = 0 + 19.6*0.5 = 9.8 V1 = 3.13 m/s. M1*g = 25N. M1*9.8 = 25 M1 = 2.55 kg M2*9.8 = 40N. M2 = 4.08 kg M1*V1 + M2*V2 = M1*V + M2*V 2.55*3.13 + 4.08*0 = 2.55*V + 4.08*V 7.982 = 6.63V V = 1.20 m/s.
*January 22, 2015*

**Math**

1b.
*January 21, 2015*

**Physics**

X = 64.9 Y = ? Z = 87.6 = magnitude or hypotenuse. X^2 + Y^2 = Z^2 Solve for Y.
*January 21, 2015*

**Physics**

2.75*10^19electrons/30s = 9.167*10^17 electrons/s I = (9.167*10^17/62.42*10^17) * 1Amp = 0.147 Amps.
*January 21, 2015*

**physics**

Vo = 15.4m/s[34.7o] Xo = 15.4*Cos34.7 = 12.7 m/s. Yo = 15.4*sin34.7 = 8.77 m/s. Y = Yo + g*Tr = 0 @ max.ht. 8.77 - 9.8*Tr = 0 -9.8Tr = -8.77 Tr = 0.895 s. = Rise time. Tf = Tr = 0.895 s. = Fall time. Tr+Tf = 0.895 + 0.895 = 1.79 s. to hit gnd.
*January 21, 2015*

**physics**

h = Vo*t + 0.5g*t^2 Vo = 0 t = 2.88 s. g = 9.8 m/s^2 Solve for h.
*January 21, 2015*

**physics**

M2V2 = M1V1 0.00255*V2 = 10.7*4.26 Solve for V2.
*January 21, 2015*

**Math proportions**

(20min/150people) * 240people = 32 Min.
*January 21, 2015*

**Algebra 2**

g(x) = x^2 - 7x - 9 g(-1) = (-1)^2 - 7*(-1) - 9 = -1 F(g(-1)) = F(-1) F(x) = x - 2 F(-1) = -1 - 2 = -3.
*January 21, 2015*

**algebra**

m2 = m1 = -A/B = -1/1 = -1 P(0,0), m2 = -1 Y = mx + b = 0 -1*0 + b = 0 b = 0 Y = -1x + 0 Eq2: Y = -x
*January 21, 2015*

**7th grade math**

Both answers are correct!
*January 21, 2015*

**Algebra**

2(x+3) = 2x+3 2x+6 = 2x+3 2x-2x = 3-6 0 = -3? No
*January 21, 2015*

**algebra**

10in./30in. =
*January 21, 2015*

**Math (Greatest common factor)**

12 = (1*12), (2*6), (3*4). 18 = (1*18), (2*9), (3*6). 24 = (1*24), (2*12), (3*8), (4*6). CF = 1,2,3,6. GCF = 6. So we factor out 6 and the variables with the lowest exponents: 6m^2n^3(2m^3 + 3m - 4) I, normally, find the GCF by knowing that the GCF =< 12 (the smallest ...
*January 21, 2015*

**Math**

1. 6.4in * 2.54cm/in = 2. 4qts * 32oz./qt * 0.03L/oz. = 3. 10kg * 1Lb/0.454kg =
*January 21, 2015*