Thursday

September 18, 2014

September 18, 2014

Total # Posts: 9,091

**math**

2. Shifted 5units down. 5. -7x^2 + 6x + 3 = 0 Use Quadratic formula and get 2 solutions : -0.354, and 1.211. 6. Y = 3x^2 + 18x + 27 = 0 x^2 * 6x + 9 = 0 (x+3)(x+3) = 0 x+3 = 0, x = -3. x+3 = 0, X = -3. 2 solutions : -3, and -3. 11. Use Quad. Formula and get 3.54 s. 12. V = Vo...
*March 11, 2014*

**physics**

V = Vo + g*t = 0 + 10*1=10 m/s. T = 1s. d = Vo*t + 0.5g*t^2 d = 10*1 + 5*1^2 = 15 m.
*March 11, 2014*

**physics**

My answer is B also.
*March 11, 2014*

**Physics**

P = 16/12 = 1.333 s.
*March 11, 2014*

**Physics**

d = V*t = 305 m. V*(1.85/2) = 305 V = 329.7 m/s.
*March 11, 2014*

**physics**

a = (V-Vo)/t = (-8-16)/0.04 = -600 m/s^2 F = m*a = 0.2 * (-600) = -120 N.
*March 11, 2014*

**physics**

Xo = 0.9 m/s? D = Xo*t = 0.9m/s * 0.4s = 0.36 m.
*March 11, 2014*

**physics**

B. 10 m/s, North.
*March 11, 2014*

**physics**

PEmax = mg*hmax = mg*4.07 J. Change = 0-mg*4.07 = -3900 mg = 958.2 N. = Wt. of the vaulter.
*March 11, 2014*

**math**

Fp = 1.5*sin18 = Parallel Force(Wt.) Fn=1.5*cos18 = Normal or perpendicular force(Wt.).
*March 11, 2014*

**physics**

Fh = 151 Hz Vr = 28.7 m/s Vs = 343 m/s Fr = ((Vs+Vr)/(Vs-Vh)) * Fh Fr = ((343+28.7)/(343-0)) * 151 Hz = (371.7/343) * 151 = 163.6 Hz = Freq. heard by the receiver(Passenger).
*March 11, 2014*

**Physics**

P = F*d/t = 0.5 * 2.1/1.1 = 0.955 J/s = 0.955 Watts.
*March 10, 2014*

**Physics!**

PE = F*h = mg*h = 1.2*9.8 * 4 = 47.04 J.
*March 10, 2014*

**Science**

LiOH + W = 231 grams 33.7 + W = 231 W = 197.3 Grams of water. Concentration = LiOH/(W+LiOH) = 33.7/231 = 0.146 = 14.6%
*March 10, 2014*

**physics**

F*d = 25 J. F * 0.13 = 25 F = 192.3 N. k = 192.3N/0.13m = 1479N/m
*March 10, 2014*

**Physics**

b. The truck.
*March 10, 2014*

**Alegbra**

4a^2 + 9b^5 + 2a^2 + 6b^5=6a^2 + 15b^5 = 3(2a^2+5b^5).
*March 10, 2014*

**Alegbra**

(4.3*10^-8)(1.5*10^9)=6.45*10^1=6.45*10
*March 10, 2014*

**science**

1. True 2. 100kg-m/s. 5. Momentum = 52kg * 10m/s. = 520 kg-m/s 61kg * 8m/s = 488 kg-m/s
*March 10, 2014*

**physics**

What are the given angles?
*March 10, 2014*

**physics**

m = 85 kg? V = 450 L. V = 450L * 1000cm^3/L = 450,000cm^3 D = 85,000g/450,000cm^3 = 0.189 g/cm^3. Mass = 300cm^3 * 0.189g/cm^3 = 56.67 g = 0.0567 kg.
*March 10, 2014*

**integrated science**

m*g = 0.15 * 9.8 = 1.47 N. = Force of gravity. Fr = -1.47i + 50N[45o] = -1.47i + 50*cos45 + (50*sin45)i = -1.47i + 35.36 + 35.36i=35.36 + 33.89i = 49N[43.8o].
*March 9, 2014*

**physics**

a. Zero.
*March 9, 2014*

**science**

L = V/Fs = 600*10^-9 m. 300*10^6/Fs = 600*10^-9 Fs = 300*10^6/600*10^-9 = 5.*10^14 Hz = Freq. emitted by spaceship. a. L = 300*10^6/Fr = 200*10^-9 Fr = 300*10^6/200*10^-9 = 1.5*10^15 Hz. = Freq. observed by the receivers. Fr = ((Vl+Vr)/(Vl-Vs))*Fs = 1.5*10^15 ((3*10^8+0)/(3*10...
*March 9, 2014*

**physical science**

Fn = 10-3 = 7 N. = Net force.
*March 9, 2014*

**Math 12**

P = Po(1+r)^n Po = 0.85 * 275,000 = $233,750 r = (2.9%/2)/100% = 0.0145 = Semi-APR expressed as a decimal. n = 2comp/yr * 25yr = 50 Compounding periods. a. P = 233,750(1.0145)^50 = 480,124.85. 480,124.50/50 = $9,602.50 Semi-annually. 0r 480,124.85/300mo = $1600.42 Monthly. b. ...
*March 9, 2014*

**math**

0.002N = 76
*March 9, 2014*

**math**

GP = 22*6 + 0.18*2,766.50
*March 8, 2014*

**math**

C = 0.026*60000 + 0.034*(89,400-60,000) = $2559.60
*March 8, 2014*

**math**

P = 40h*8.25/h + 12h*1.5*8.25/h + 6h*2*8.25/h = $577.50
*March 8, 2014*

**Engineering science**

h = 0.5g*t^2 = 4.9*4.5^2 = 99.23 m. PE = mg*h = 6*9.8 * 99.23 = 5834 J.
*March 8, 2014*

**Physics**

m*g = 5.36k * 9.8N/kg = 52.53 N. = Wt. of object. a. KE = 0 J. = Initial KE V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*1 = 19.6 V = 4.43 m/s. KE = 0.5m*V^2 = 2.68*4.43^2 = 52.59 J. b. V^2 = Vo^2 + 2g*h V^2 = 4.43^2 + 19.6*1 = 39.22 V = 6.26 m/s. KEo = 2.68*4.43^2 = 52.59 J. KE = 2.68*6....
*March 8, 2014*

**physics**

Tr = To + (-Vo)/g = 4 + (-112.8)/-9.8 = 15.51 s. = Rise time. hmax = ho + (V^2-Vo^2)/2g hmax = 225.6 + (0-(112.8)^2)/-19.6 = 1506 m. Above gnd. hmax = 0.5g*t^2 = 1506 m. 4.9t^2 = 1506 t^2 = 307.3 Tf = 17.53 s. = Fall time. T = Tr + Tf = 15.51 + 17.53 = 33.0 s. = Time in air.
*March 8, 2014*

**business math**

8.25(40+18+12) = 70 * 8.25 = $577.50
*March 8, 2014*

**physics**

F1 = (x,y) = (3.85N,-2.85N) F2 = (x,y) = (2.95N,-3.65N). a. Fr=X+Yi=(3.85+2.95) + (-2.85i-3.65i)= 6.8 - 6.5i = 9.41N[316.3o] = Resultant force. 2.10kg particle Location: (x,y) = (-2.30m,-3.60m) a(x) = Fx/mass = 6.8/2.1 = 3.24 m/s^2 Vx=Vox + a*t = 0 + 3.24*11.8= 38.21 m/s. a(y...
*March 7, 2014*

**physical science**

d = 200mi/h[120o] * 1.5h = 300mi[120o] X = 300*cos120 = -150 mi = 150 mi West. Y = 300*sin120 = 260 mi North.
*March 7, 2014*

**physics**

P=F*V = mg*V = 106*9.8 * 34.5=35,839 J/s =35,839 Watts.
*March 7, 2014*

**math**

11. Y = (1/2)x^2 + 2x - 3 Use Quadratic Formula and get: X = 1.16228, and -5.16228. 27. 3x^2-5x = -3x^2+6 3x^2+3x^2-5x = 6 6x^2 - 5x - 6 = 0 Use the AC method of factoring: A.C = 6*(-6) = -36 = 3*(-12)=4*(-9). Choose the pair of factors whose sum = B or -5: We choose 4, and -9...
*March 7, 2014*

**Math Geometry**

1 1/4 in. = 5/4 in. Width = W in. Length = 5/4 * W = 5W/4 in. Area = Length * Width = 5W/4 * W = 180 1n^2. 5W^2/4 = 180 Multiply both sides by 4: 5W^2 = 720 W^2 = 144 W = 12 in. = Width 5/4 * 12 = 15 in. = Length.
*March 7, 2014*

**Science**

V^2 = Vo^2 + 2g*h = 0 + 19.6*3 = 58.8 V = 7.67 m/s. V^2 = Vo^2 + 2g*h = 0 @ max ht. Vo^2 - 19.6*2.2 = 0 Vo^2 = 43.12 Vo = 6.57 m/s. a = (-6.57-7.67)/0.002s = -7120 m/s^2. F = m*a = 0.20 * (-7120) = -1424 N.
*March 7, 2014*

**physical**

Xo = 250 km/h A = 30o Vo = Xo/cosA = 250/cos30 = 288.7 km/h. Yo = Vo*sin30 = 288.7*sin30 = 144.3 km/h
*March 7, 2014*

**Physics**

See previous post: Wed,3-5-14.9:29 PM.
*March 7, 2014*

**Science**

My answer is "a" also.
*March 6, 2014*

**physic**

A+B = 7[45] + 10[45] = 17[45o]. Since the angles are equal, we add the vectors directly.
*March 6, 2014*

**physics**

I = V/R = 1.5/3 = 0.5A. The voltage across each resistor is 1.5 volts.
*March 6, 2014*

**physics**

R = V/I = 2/3.2*10^-3
*March 6, 2014*

**geometry**

X = 4 r = 7 = hyp. cos A = X/r = 4/7 = 0.57143 A = 55.15o
*March 6, 2014*

**math**

Value = 50,000 + 0.03*3*50,000=$54,500
*March 6, 2014*

**physics**

Vs = 3m/s[135o] + 2m/s[270o] X = 3*cos135 = -2.12 m/s. Y = 3*sin135 + 2*sin270o = 0.1213 m/s. Tan Ar = Y/X = 0.1213/-2.12 = -0.05723 Ar = -3.275o = Reference angle. A = -3.275 + 180 = 176.7o Vs = X/cosA = -2.12/cos176.7=2.123 m/s. [176.7o]
*March 5, 2014*

**Physics**

a. V^2 = Vo^2 + 2g*h = 0 @ max ht. Vo^2 - 19.6*1.45 = 0 Vo^2 = 19.6*1.45 = 28.42 Vo = 5.33 m/s = Initial velocity after striking the floor. Impulse = m*V = 0.20*5.33 = 1.067 kg-m/s b. V^2 = Vo^2 + 2g*h = 0 + 19.6*1.95 = 38.22 V = 6.18 m/s. = Velocity just before striking the ...
*March 5, 2014*

**Physics**

a. D = d1 + d2 + d3 = 70*(45/60) + 95*(10/60) + 55*(30/60) = 95.83 km. T = 45 + 10 + 30 + 20=105 min=1.75 h. Avg. Speed=D/T=95.83km/1.75h=54.8 km/h. NOTE: My procedure is the same as Bob's, but he forgot to include the 20 min for eating and buying gas. Your answer in Part...
*March 5, 2014*

**phy**

Vo = 2m/s[-45o] Xo=2*cos(-45)=1.414 m/s=Hor. component. Yo=2*sin(-45)=-1.414 m/s=Ver. component. Depth = Yo*t + 0.5g*t^2 = -1.414*1.3 + 4.9*1.3^2 = 6.44 m.
*March 5, 2014*

**physics**

P2/P1 = ((2V)^2/R)/(V^2/R)= (4V^2/R)*R/V^2=4V^2/V^2 = 4 Alternate Method: P1 = V1^2/R = 10^2/100 = 1. Watt. P2 = V2^2/R = 20^2/100 = 4 Watts. P2/P1 = 4W/1W = 4 So the power is increased by a factor of 4.
*March 5, 2014*

**Physics**

F = 10N[45o] + 8N[330o] -7.5N X = 10*cos45 + 8*cos330 - 7.5 = 6.50 N. Y = 10*sin45 + 8*sin330 = 3.07 N. Tan A = Y/X = 3.07/6.50 = 0.47247 A = 25.29o Fr = X/cosA = 6.50/cos25.29=7.19N[25.29] = Resultant force. a = Fr/m = 7.19[25.29o]/49=0.147[25.29]
*March 4, 2014*

**Physics**

L = V/F = 0.333 m. L = V/15000 = 0.333 V = 0.333 * 15,000 = 4995 m/s. 4995 - 343 = 4652 m/s faster.
*March 4, 2014*

**physics**

X = 130 km/h Y = 275 km/h V^2 = 130^2 + 275^2 = 92,525 V = 304.2 km/h.
*March 4, 2014*

**Physics**

F = 4.8 - 0.6 = 4.2 N.
*March 4, 2014*

**Math**

Y = 2x + 3 Eq1: -2x + y = 3 X = 1 - 2y Eq2: x + 2y = 1 Multiply Eq2 by 2 and add Eq1 and Eq2: -2x + y = 3 +2x + 4y = 2 sum: 5y = 5 Y = 1 In Eq2, replace Y with 1 and solve for x: x + 2*1 = 1 X = -1. Solution set: (x,y) = (-1,1). One common solution.
*March 4, 2014*

**Basic algebra**

Speed = r mi/h going to work. Speed = (r+10)m/h returning. d = r mi/h * 1 h = (r+10)mi/h * 0.5h r * 1 = (r+10) * 0.5 r = 0.5r + 5 0.5r = 5 r = 10 mi/h r+10 = 10+10 = 20 mi/h d = 10 * 1 = (10+10) * 0.5 = 10 mi.
*March 4, 2014*

**Physc**

Tr = 20/2 = 10 s. = Rise time. Range = Xo * T = 80 m. Xo * 20 = 80 Xo = 4 m/s = Hor. component of initial velocity. a = 0 = Hor. acceleration. a = g = 9.81 m/s^2. = Ver. acceleration.
*March 4, 2014*

**Physics**

Wt. of crate = m * g = 3.2kg * 9.8N/kg = 31.36 N. Fp = 31.36*sin35 = 17.99 N. = Force parallel to the incline. F = Fp*cos35 = 17.99*cos35 = 14.74 N.
*March 4, 2014*

**physics**

V^2 = Vo^2 + 2g*h V^2 = !0^2 + 19.6*75 = 1570 V = 39.62 m/s KE = 0.5m*V^2 = 1*39.62^2 = 1570 J.
*March 3, 2014*

**algebra**

X dimes. (15-X)Qtrs. 0.10x + 0.25(15-x) = $2.85 10x + 25(15-x) = 285 10x + 375-25x = 285 -15x = 285-375 = -90 X = 6 15-X = 15-6 = 9
*March 3, 2014*

**physics**

a=(V^2-Vo^2)/2d=(0-15^2)/14=-16.07 m/s^2 d = (V^2-Vo^2)/2a d = (0-(32^2))/-32.14 = 31.86 m.
*March 3, 2014*

**Physics**

F = m*g = 0.05kg * 9.8N/kg = 0.49 N. d = 18-12 = 6 cm = 0.06 m. k = 0.49N/0.06m = 8.17N/m.
*March 3, 2014*

**Consumer Math**

Po = $235,000 APR = ? T = 30 yrs?
*March 3, 2014*

**Alegbra**

Eq1: Po1+ Po2 = 5000 Po1*0.05*1 + Po2*0.08*1 = 331 0.05Po1 + 0.08Po2 = 331 Eq2: 5Po1 + 8Po2 = 33100 Multiply Eq1 by -5 and add Eq1 and Eq2: -5Pol - 5Po2 = -25,000 +5Po1 + 8Po2 = 33,100 Sum: 3Po2 = 8100 Po2 = $2700 Pol = 5000-2700 = $2300.
*March 2, 2014*

**Math**

See previous post.
*March 2, 2014*

**MATH**

Po = Amt. invested @ 6%. Po/3 = Amt. invested @ 8% Po + Po/3 = $33,000 3Po + Po = 99000 4Po = 99000 Po = $24,750 @ 6%.(2nd security). Po/3 = 24,750/3 = $8,250 @ 8%.(1st security). Int. = 24,750*0.06*1yr + 8,250*0.08*1yr= $2145.
*March 2, 2014*

**mat116**

Y = 3x-7 Y = 3x+5 Each has a slope of 3. Y-intercepts are -7 and 5.
*March 2, 2014*

**science**

X = -122 km Y = -15 km Vw = d/t = 15/0.52 = 28.8 km/h B. Tan Ar = Y/X = -15/-122 = 0.12295 Ar = 7.0o = Reference angle. A = 7 + 180 = 187o = 7o S of W. C. X = 225 km/h. Y = 42 km/h. Tan A = 42/225 = 0.18667 A = 10.57o S of W. Pilot should head 10.57o N of W.
*March 2, 2014*

**Physics**

a. Range = Vo^2*sin(2A)/g = 60 m. Vo^2*sin(60)/9.8 = 60 0.0884Vo^2 = 60 Vo^2 = 679 Vo = 26.06 m/s.[30o] b. Yo = 26.06*sin30 = 13.03 m/s = Ver. component. hmax = (Y^2-Yo^2)/2g hmax = (0-13.03^2)/-19.6 = 8.66 m.
*March 2, 2014*

**Pre-Calculus**

Vo = 32Ft/s[35o] Xo = 32*cos35 = 26.21 Ft/s. Yo = 32*sin35 = 18.35 Ft/s. a. Y = Yo + g*Tr = 0 @ max. ht. Tr=(Y-Yo)/g = (o-18.35)/-32.4=0.566 s = Rise time or time to reach max. ht. hmax = ho + Yo*t + 0.5g*Tr^2 hmax = 4.5 + 18.35*0.566 - 16.2*0.566^2 = 9.70 Ft above gnd. b. ...
*February 28, 2014*

**Physics**

h = 0.5g*t^2 = 4.9*2^2 = 19.6 m.
*February 28, 2014*

**Math**

V = 325mph[340o] + 30mph[300o] X = 325*cos340 + 30*cos300 = 320.4 mph = Hor. component. Y = 325*sin340 + 30*sin300 = -137.1 mph = Ver. component. TanA = Y/X = -137.1/320.4 = -42802 A = -23.17o,CW = 336.8 CCW. V = 320.4/cos336.8 = 348.6mph[336.8o]
*February 28, 2014*

**physics**

Work = F*d = 2 * 0 = 0
*February 28, 2014*

**physics**

d = r*t = 3 m. r * 0.3 = 3 r = 10 m/s. = Rate of speed.
*February 28, 2014*

**Algebra**

1. Quadratic. 2. h = Yo*0.75 - 16.2*0.75^2 = 77 Ft. Yo*0.75 - 9.11 = 77 0.75Yo = 86.11 Yo = 114.82 Ft/s. Y = Yo + g*Tr = 0 @ max. ht. Tr=(Y-Yo)/g = (0-114.82)/-32.4 = 3.54s. = Rise time. hmax = Yo*Tr + 0.5g*Tr^2 hmax=114.82*3.54 - 16.2*3.54^2=203.8 Ft. Eq: h = -16.2t^2 + 114.82t
*February 28, 2014*

**math**

r mi/h When leaving. (r-20)mi/h When returning. (r + (r-20))22 = 1400 mi. r + 22r-440 = 1400 23r = 1400+440 = 1840 r = 80 mi/h r-20 = 80-20 = 60 mi/h. = Speed on return trip.
*February 27, 2014*

**Math**

P(2,-7), M(x,y), Q(-4.-1) X = (x1+x2)/2 = (2+(-4))/2 = -1. Y = (y1+y2)/2 = (-7+(-1))/2 = -4. M(-1,-4)
*February 27, 2014*

**Physics**

a. Speed = 120m/20s = 6 m/s. b. Speed = (70m-30m)/(10s-5s) = 8 m/s. c. No, Jack did not travel at a constant speed: 30m/5s = 6 m/s after 5 s. 70m/10s = 7 m/s after 10 s.
*February 27, 2014*

**math**

a. $28/mo * 24mo. = $672. b. $672 - $500 = $172 c. $500/$28/mo = 18 Mo.
*February 27, 2014*

**physics**

See previous post: Wed, 2-26-14, 9:07 PM.
*February 27, 2014*

**Physics**

post it.
*February 27, 2014*

**Physics**

h = 0.5g*t^2 = 150 m. 4.9t^2 = 150 t^2 = 30.61 t = 5.53 s. = Fall time. d = Xo * t = 150m/s * 5.53 s = 830 m.
*February 27, 2014*

**Alegbra**

Width = W Ft. Length = (2W + 3)Ft P = 2W + 2(2W+3) = 72 2W + 4W+6 = 72 6W = 72-6 = 66 W = 11 Ft. Length = 2*11 + 3 = 25 Ft
*February 27, 2014*

**physics**

Tr = 2.68/2 = 1.34 s. = Rise time. V = Vo + g*Tr = 0 @ max. ht. Vo = -(g*Tr) = -(-9.8*1.34) = 13.13 m/s. D = h - ho = 1m - 1m = 0
*February 26, 2014*

**physical science**

a = (V-Vo)/t = (20-0)/15 = 1.33 m/s^2.
*February 26, 2014*

**physics**

a = (V-Vo)/t = (11.9-0)10 = 1.19 m/s^2.
*February 26, 2014*

**Physics**

Correction: Work = 180*cos33 * 1577 = 238,065 J.
*February 26, 2014*

**Physics**

Vo = 11km/h = 11,000m/3600s = 3.056 m/s. d=r*t=3.056m/s * 8.6min * 60s/min=1577 m Work = F*d = 180*cos33 * 1577 = 238 J. Power = F*V = 180*cos33 * 3.056 = 461.3 J./s = 461.3 Watts.
*February 26, 2014*

**Physics**

Dx = Xo * T = 59 m. Xo * 4.8 = 59 Xo = 12.29 m/s = Hor. component of initial velocity. Vo = Xo/cosA = 12.29/cos43 = 16.81 m/s k = F/d = m*g/d = 72*9.8/3.7m=191N/m
*February 26, 2014*

**Physics**

a.=Wt. of skier=m*g=79kg9.8N/kg=774.2 N. Fp = 774.2*sin30 = 387.1 N. = Force parallel to the slope. Work = F*d = 387.1 * 80 = 30,968 J. b. Power=F*V = 387.1 * 3.4=1316 J./s. = 1316 Watts. 1316W * 1hp/746W. = 1.76 hp.
*February 26, 2014*

**Physics 130**

PEmax = mg*hmax - FE PEmax = 20*9.8*25 - FE = (4900-FE) J. KE + PE = 4900 - FE 0.5m*V^2 + mg*h = 4900-FE 10*16^2 + 196*10 = 4900-FE 2560 + 1960 = 4900-FE 4520 = 4900-FE FE = 4900-4520 = 380 J. = Energy loss due to friction.
*February 25, 2014*

**math**

r = d/t = (1500-1200)/1min = 300 m/min = Rate of speed. T = 1500m * 1min/300m = 5 Min.
*February 25, 2014*

**physics**

V^2 = X^2 + Y^2 = 22^2 + 25^2 = 1109 V = 33.3 m/s.
*February 25, 2014*

**physics**

PE = mg*h = 0.272*9.81 * 0.71 = 1.89 J.
*February 25, 2014*

**math**

AD/AB = DE/BC AD/6 = 20/8. Solve for AD.
*February 25, 2014*

**physics**

A. Work = F*cosA * d = 43 J. 60*cosA * 2.0 = 43 120*cosA = 43 cosA = 0.35833 A = 69o B. a = (V^2-Vo^2)/2d a = (2.7^2-0)/4 = 1.82 m/s^2. F*cos69 = m*a 60*cos69 = m*1.82 m = 60*cos69/1.82 = 11.80 kg.
*February 25, 2014*

**physics**

Incomplete.
*February 25, 2014*

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