Monday

January 23, 2017
Total # Posts: 13,051

**Math**

db = 10*Log(Po/75) = 12. Log(Po/75) = 1.2, Po/75 = 10^1.2, Po = 1189 W.

*December 14, 2016*

**Physics**

a. Vo = 20m/s[45o]. Xo = 20*Cos45 = 14.14 m/s. Yo = 20*sin45 = 14.14 m/s. Y = Yo + g*t = 0. 14.14 - 9.8t = 0, t = 1.44 s. b. Y^2 = Yo^2 + 2g*h = 0. (14.14)^2 - 19.6h = 0, h = ?. c. Range = Vo^2*sin(2A)/g. A = 45o. d. T = Tr+Tf. Tf = Tr, T = Tr+Tr = 1.44 + 1.44 = 2.88 s. d.

*December 14, 2016*

**Math**

Invested: Po @ 2%. (2Po+2300) @ 9%. t = 1 yr.? I = Po*r*t + (2Po+2300)*r*t = 647. Po*0.02*1 + (2Po+2300)*0.09*1 = 647, 0.02Po + 0.18Po + 207 = 647, 0.20Po = 440, Po = $2200. 2Po+2300 = 2*2200 + 2300 = $6700.

*December 13, 2016*

**Mathematics**

1. (8,11). y/x = 11/8, Y = 1.375x. 2. correct. 3. y/x = 232/4 = 58/1. 4. (2,5), (8,3). m = (3-5)/(8-2) = -2/6 = -1/3.

*December 13, 2016*

**math**

Correction: 360cm^3/2^3 = 45 Cubes.

*December 13, 2016*

**physics**

Work = KE2-KE1 = KE2-0 = KE2. KE2 = 0.5M*V^2 = 10,000 J. 500*V^2 = 10,000, V = ?.

*December 12, 2016*

**Physics**

a. M*g = 1.35 * 9.8 = 13.2 N. = Wt. of book. = Normal force(Fn). Fs = us*Fn = 0.45 * 13.2 = 5.95 N. F-Fs = M*a. F = Fs+M*a = 5.95+M*0 = 5.95 N. b. Fk = uk*Fn = 0.30 * 13.2 = 3.96 N. F-Fk = M*a. a = (F-Fk)/M. c. Fap-Fk = M*a. Fap = Fk+M*a = 3.96 + M*0 = 3.96 N. = Force applied...

*December 12, 2016*

**Physics**

e. Fnet = M*a. a = Fnet/M.

*December 12, 2016*

**Physics**

a. M*g = 475 * 9.8 = 4655 N. = Wt. of sleigh. = Normal force(Fn). b. Fs = u*Fn = 0.20 * 4655 = c. Fk = uk*Fn = 0.15 * 4655 = d. Fnet = Fh-Fk = 150,000-4655 =

*December 12, 2016*

**Science**

F = M*a. = 20. a = 20/M = 20/60 = 0.333 m/s^2.

*December 11, 2016*

**physics**

See previous post: Sun, 12-11-16, 7:32 PM.

*December 11, 2016*

**Physics**

M*g = 180 * 9.8 = 1764 N. = Wt. of trunk. Fn = 1764 - 400*sin15 = 1661 N. = Normal force. Fap*Cos A-Fk = M*a. Fk = Fap*Cos A-M*a = 400*Cos15-M*0 = 386.4 N. = Force of kinetic friction. Fk = u*Fn = 386.4. u = 386.4/Fn = 386.4/1661 = 0.233 = Coefficient of kinetic friction.

*December 11, 2016*

**Physics**

3. V = Vo + a*t = 0. 25 + a*8 = 0, a = -3.1025 m/s^2 Thrust = M*a = 958/9.8 * (-3.125) = -305.5 N. 5. M*g = 3.0 * 9.8 = 29.4 N. = Wt. of block = Normal(Fn). Fs = u*Fn = 0.4 * 29.4 = 11.8 N. 7. M*g = 50 * 9.8 = 490 N. = Wt. of box = Normal(Fn). Fk = u*Fn = 0.35*490 = 171.5 N. F...

*December 11, 2016*

**Physics**

Y^2 = Yo^2 + 2g*h = 0. Yo^2 - 64*20 = 0, Yo = 35.8 Ft/s. Vo*sin30 = 35.8, Vo = 71.6 Ft/s.

*December 11, 2016*

**algebra**

See previous post: Sun, 9-11-16, 2:24 PM.

*December 11, 2016*

**algebra**

Donuts: $X ea. Coffee: $Y ea. Eq1: 3x + 4y = 4.91 Eq2: 5x + 6y = 7.59 Multiply Eq1 by 5 and Eq2 by (-3): +15x + 20y = +24.55 -15x - 18y = -22.77 Sum: 2y = 1.78, Y = 0.89 In Eq1 replace Y with 0.89: 3x + 4*0.89 = 4.91. X = ?

*December 11, 2016*

**algebra 1**

Right!

*December 11, 2016*

**algebra 1**

(-3,-7), (-5,-7). m = (-7-(-7))/(-5-(-3)) = 0/-2 = 0. Y = mx + b = -7. 0*x + b = -7, b = -7, Eq: Y = -7 = A horizontal line.

*December 11, 2016*

**algebra 1**

X 2-pointers. (16-x) 3-pointers. 2x + 3(16-x) = 38, 2x + 48 - 3x = 38, X = 10. 16-x = 16-10 = 6.

*December 11, 2016*

**algebra**

X 2-pointers. (16-x) 3-pointers. 2x + 3(16-x) = 38, 2x + 48 - 3x = 38, X = 10. 16-x = 16-10 = 6.

*December 11, 2016*

**math**

post it.

*December 11, 2016*

**Algebra**

x^2 - 6x + 9 > 0. (x-3)^2 > 0, Take sqrt of both sides: x-3 > 0, X > 3.

*December 10, 2016*

**Algebra**

h(t) = 240 - 16tT^2 = 0. 16t^2 = 240, t = 3.87 s. 6

*December 10, 2016*

**Math**

a. Net Cash = 780,000 - 270,000 - 60,000 - 0.05(780,000-200,000) = $421,000.

*December 10, 2016*

**Algebra**

18a. F(x) = x - 5. 18b. F(x) = x - 0.25x = x(1-0.25) = 0.75x.

*December 10, 2016*

**math**

Randy: 28min.-11.0 s. Julie: 28min.-03 s. Pat: 28min.-2.9 s.

*December 8, 2016*

**Science physics**

See Related Questions: Feb 13, 2008, 11:12 PM.

*December 8, 2016*

**Physics**

%Eff. = Output/Input * 100% = 40/150 * 100% =

*December 7, 2016*

**Trigonometry**

correction: 2.5rev/10s * 6.28rad/rev = 1.57 rad/s.

*December 6, 2016*

**Trigonometry**

Va = 2.5rev/10s. * 6.28rad/rev = 15.7 rad/s.

*December 6, 2016*

**math**

d = V*t = 21*10^6 m. t = 21*10^6/3*10^8 = 7*10^-2 s. = 70 ms.

*December 6, 2016*

**Algebra**

2. (-2,-3), (1,1). m = (y2-y1)/(x2-x1) = (1-(-3))/(1-(-2)) = (1+3)/(1+2) = 4/3. 4. 24/8 = y/10, Y = 30. 5. Y = (2/3)x + 9. 6. (1,-3), (3,1). m = (1+3)/(3-1) = 2. Y = 2x + b = -3. 2*1 + b = -3, b = -5. Eq: Y = 2x - 5.

*December 5, 2016*

**Mathematics**

I = Po*r*t = 800*0.02*2 = $32.

*December 5, 2016*

**Physics**

M*g = 15 * 9.8 = 147 N. = Wt. of box. Fp = 147*sin30 = 73.5 N. = Force parallel to the incline. Fx = Fp*Cos30 = 73.5*Cos30 = 63.6 N.

*December 4, 2016*

**Physics**

M*g = 1.5, M = 1.5/g = 1.5/9.8 = 0.153 kg. PE = Mg*h = 1.5 * 4 = 6.0 J. V^2 = Vo^2 + 2g*h = 0 + 19.6*4 = 78.4 (m/s)^2. KE = 0.5M*V^2 = 0.5*0.153*78.4 = 6.0 Joules. Energy Lost = PE - KE = 6-6 = 0.

*December 4, 2016*

**PreCalc**

A = Po(1+r)^n. Po = $14,000. r = 0.052/12 = 0.0043/mo. n = 12comp./yr. * t yrs. = 12t compounding periods.

*December 4, 2016*

**Maths**

Bisi is X yrs. old. Musa is (x+12) yrs. old. Four yrs. later: Bisi is (x+4) yrs. old. Musa is 2(x+4) = 2x+8. 2x+8 = (x+4) + 12. 2x+8 = x+16, X = 8. x+12 = 8+12 = 20.

*December 4, 2016*

**Physics**

Vo = 5.6m/s[10o]. Xo = 5.6*Cos10 = 5.51 m/s. Yo = 5.6*sin10 = 0.97 m/s. Y^2 = Yo^2 + 2g*h = 0. 0.97^2 - 19.6h = 0, h = 0.048 m. Y = Yo + g*Tr = 0. 0.97 - 9.8Tr = 0, Tr = 0.099 s. = Rise time. 0.5g*Tf^2 = (0.048+3). 4.9Tf^2 = 3.048, Tf = 0,789 s. = Fall time. Dx = Xo*(Tr+Tf) = ...

*December 4, 2016*

**MATH**

11,450-10,000 = $1450 = profit on the remaining 2/3. 1450/10,000 * 100% = 14.5 % = Gain % on remaining 2/3.

*December 4, 2016*

**MATH**

15,000/3 = $5,000 = selling price to break even. 0.95 * 5000 = $4750 = selling price. Loss = 5000-4750 = $250. 10,000 + 250 = $10,250 = selling price to break even. 15,000 * 1.08 = $16,200 = total selling price for 8% profit. 16,200-4750 = $11,450 = Selling price of the ...

*December 4, 2016*

**Math**

M*g = 2 * 9.8 = 19.6 N. = Wt. of flowers. Fp = 19.6*sin A. = Force parallel with incline. Fn = 19.6*Cos A. = Normal force. Fs = u*Fn = 0.4*19.6*Cos A = 7.84*Cos A. = Force of static friction. Fp-Fs = M*a. 19.6*sin A-7.84*Cos A = M*0 = 0, 19.6*sin A = 7.84Cos A, 19.6*sin A/Cos ...

*December 4, 2016*

**mathematics**

A = L*W + 2W*h + 2L*h. A = 11*8 + 2(8*5) + 2(11*5) = 278 ft^2.

*December 4, 2016*

**Math**

(Vb-Vr) * T1 = 36 (Vb-Vr)3 = 36 Eq1: Vb - Vr = 12 (Vb+Vr) * T2 = 36 (Vb+Vr)2 = 36 Eq2: Vb + Vr = 18 Add Eq1 and Eq2: Vb - Vr = 12. Vb + Vr = 18. Sum: 2Vb = 30, Vb = 15 mi/h. In Eq1, replace Vb with 15: 15 - Vr = 12, Vr = 3 mi/h.

*December 4, 2016*

**Math**

Please proofread your problem; it doesn't make sense as written.

*December 4, 2016*

**Propotion**

When speed = 60km/h. time = T1. When speed = 80 km/h, time = (60/80)T1 = 0.75T1.

*December 4, 2016*

**ALGEBRA PLZ HELP!1**

L = 2in * 12ft/1n = 24 ft. W = 1.75in * 12ft/1n =

*December 4, 2016*

**Math**

10/35 = 8/W. W = ?.

*December 4, 2016*

**Math**

Length = 12 cm. Width = 1/1.414 * 12cm = 8.49 cm. Area = L * W.

*December 4, 2016*

**math**

65%/35% * 20Litres. = 37.1 Litres.

*December 3, 2016*

**Physics**

Va = 65mi/h * 1600m/mi * 1h/3600s = 28.9 m/s. F1 = (Vs+Vp)/(Vs-Va) * Fa. F1 = (330+0)/(330-28.9) * 500 = 548.0 Hz. F2 = (330-0)/(330+28.9) * 500 = 459.7 Hz. F1-F2 = 548 - 459.7 = 88.3 Hz. = Total shift in freq.

*December 3, 2016*

**math**

P = Po(1+r)^n. Po = 200 r = (9%/12)/100% = 0075/mo. n = 1comp./mo. * 24mo = 24 Compounding periods. P = 200(1.0075)^24 = $239.28

*December 2, 2016*

**FINANICIAL**

Po = 46,000/(1.0755)^12 = $19,205.82

*December 2, 2016*

**FINANICIAL**

P = Po(1+r)^n = 46,000. r = 7.55%/100% = 0.0755. n = 1comp./yr. * 12yrs. = 12 Compounding periods. Po = ?.

*December 2, 2016*

**Physics**

h = 0.5g*t^2 = 2.4-0.91. 4.9t^2 = 1.49. t1 = 0.551 s. d1 = Xo*t1 = 22.3 * 0.551 = 12.3 m. = Distance from back line to net. 0.5g*t2^2 = 2.4. 4.9t2^2 = 2.4, t2 = 0.70 s. to fall to gnd. d2 = Xo*t2 = 22.3 * 0.7 = 15.6 m. = Maximum distance travelled. a. Yes. b. d = 12.3 + 6.4 = ...

*December 1, 2016*

**algerba**

X pennies, and Y nickels. Eq1: 1x + 5y = 920 cents. Eq2: 5x + 1y = 2680 cents. -5x - 25y = -4600 +5x + 1y = 2680 Sum: -24y = -1920 Y = 80 nickels. In Eq1, replace Y with 80: x + 5*80 = 920, X = 520 Pennies.

*December 1, 2016*

**MATH**

Po = 46,000/(1.0755^12) = $19,205.82 = Amt. invested now.

*December 1, 2016*

**math algebra**

A = P*e^rt. P = $2,000 rt = 0.0475/yr. * 30yrs. = 1.425. A = ?.

*December 1, 2016*

**Math**

W = -(40*Cos30+60*Cos(theta)). -40*sin30 + 60*sin(theta) = 0. 60*sin(theta) = 40*sln30, sin(theta) = 2/3 * sin30 = 0.3333, theta = 19.5o W = -(40*Cos30+60*Cos19.5) = -91.2 N.

*December 1, 2016*

**physics**

6.28rad/rev * 2rev = 12.56 rad. 12.56rad/24h * 1h/3600s = 1.45*10^-4 rad/s.

*December 1, 2016*

**physics**

M*g = 30, g = 30/M.

*December 1, 2016*

**physics**

d = 0.5g*t^2.

*December 1, 2016*

**Science**

d = 0.5a*t^2 = 1500 m. 2.5*t^2 = 1500, t = 24.5 s.

*December 1, 2016*

**physics**

Range = Vo^2*sin(2A)/g.

*November 30, 2016*

**Physics**

See previous post.

*November 30, 2016*

**Science Physics**

See previous post: Wed, 11-30-16, 11:53 AM.

*November 30, 2016*

**Science, physics**

You have 2 vectors: one pointing north and one pointing west. Vr = -6 + 15i = 16.2km/h[-68.2o] = 16.2km/h[68.2o] N. of W.

*November 30, 2016*

**Science**

KE = 0.5M*V^2. KE = 0.5M*(V/2)^2 = 0.5M*V^2/4. So KE is reduced by a factor of 4(divided by 4).

*November 30, 2016*

**physics**

a. Vm - 2i = 4.2. Vm = 4.2 + 2i = 4.65m/s[25.6o] N. of E. = Velocity and Heading. b. Vm = 4.65m/s[25.6o]. c. d = Vm*t = 800. t = 800/Vm = 800/4.65 = 172 s.

*November 30, 2016*

**Algebra**

When B^2-4AC < 0, No real solutions. When B^2-4AC = 0, One real solution. When B^2-4AC > 0, Two real solutions.

*November 30, 2016*

**Algebra**

1. X = (-B +- Sqrt(B^2-4AC))/2A. X = (-0.8 +- sqrt(0.64+2.96))/-0.04 = -27.43, and 67.43. Solution: X = 67.43. 2. 0 = 5x^2+2x-12. B^2 - 4AC = 4 - (-240) = 244. Two solutions. 3. -8x^2 - 8x - 2 = 0. B^2-4AC = 64 - 64 = 0. One solution.

*November 30, 2016*

**consumers math**

Ar = Ab-I = Ab - Ab*r*t. Ar = 290 - 290*(0.16/360)*90, Ar = 290 - 11.60 = $278.40 = Amt. received(proceeds). I = $11.60.

*November 30, 2016*

**precalculus**

See previous post: Tue, 11-29-16, 3:33 PM.

*November 29, 2016*

**Math**

1. When X = 5, Y = 3*5 = 15. Since Y varies directly with X, Y will ALWAYS be 3 times X: Y = 3x. 2. Slope-Intercept Form: Y = (-2/3)x - 1. Multiply both sides by 3: 3y = -2x - 3, Add 2x to both sides: 2x + 3y = -3,

*November 29, 2016*

**pre-calculus**

A. 1rev/5.4min * 6.28rad/rev = 1.16 rad/min. B. Circumference = pi*2r = 3.14 * 78 = 245.0 feet. 5.6ft/s * 6.28rad/245ft. = 0.144 rad/s. C. 0.9rad/3s = 0.3rad/s.

*November 29, 2016*

**math**

See previous post: Tue, 11-29-16, 5:38 PM.

*November 29, 2016*

**maths**

a. 4.8kg/(0.25kg/pk.) = 19.2 or 19 packets. b. 250g/pk. * 0.2pk. = 50 g.

*November 29, 2016*

**pre calculus**

Eq2 was obtained by multiplying both sides of Eq1 by 2. Therefore, the two Eqs are identical. So we have an infinite number of solutions.

*November 29, 2016*

**pre calculus**

Eq2 was obtained by multiplying both sides of E

*November 29, 2016*

**science**

Circumference = pi*2r = 3.14 * 0.5 = 1.57 m. Vo = 72,000m/3600s * 6.28rad/1.57m = 80 rad/s. d = 20rev * 6.28rad/rev = 125.6 rad. V^2 = Vo^2 + 2a*d. V = 0, Vo = 80 rad/s, d = 125.6 rad, a = ?. "a" will be negative.

*November 29, 2016*

**Science**

Are you sure the time is only o.5 s.?

*November 28, 2016*

**Math**

Eq1: Vm - Vc = 15. Eq2: 0.5Vm + Vc = 12. Sum: 1.5Vm = 27, Vm = 18 mi/h. In Eq1, replace Vm with 18 and solve for Vc.

*November 28, 2016*

**Math**

d1 = d2. (Vp+Vw)*t1 = (Vp-Vw)t2. (150+Vw)*2 = (150-Vw)*3. Vw = ?.

*November 28, 2016*

**physics**

See Related Questions: Thu, 7-21-16, 1:58 AM.

*November 28, 2016*

**History**

The space is between the words the and act

*November 27, 2016*

**History**

The purpose of the act was to provide land to railroad companies so that a transcontinental railroad could be built.

*November 27, 2016*

**History**

Fill in the blank The purpose of the act was to provide land to railroad companies so that a transcontinental railroad could be built.

*November 27, 2016*

**History**

What are 2 things the railroad supplied from the west to other parts of the world ? What technology was used to show that the railway was complete ?

*November 27, 2016*

**precalculus**

Law of Sine: a/sin A = b/sin B. 9.4/sin150 = 4.8/sin B 9.4*sin B = 4.8*sin150, 9.4*sin B = 2.4, sin B = 0.25532, B = 14.8o. A+B+C = 180o. 150 + 14.8 + C = 180, C = 15.2o. a/sin A = c/sin C. c = ?.

*November 27, 2016*

**physics**

b. KE1 = 0.5M1*V1^2 + 0.5M2*V2^2, KE1 = 500*25^2 + (1000*15i^2), KE1 = 312,500 + 225,000 = 537,500 J. = KE before collision. KE2 = 0.5M1*V + 0.5M2*V. KE2 = 500*13^2 + 1000*13^2 = 253,500 J. = KE after collision. KE1-KE2 = KE lost after collision.

*November 27, 2016*

**physics**

a. M1V1 + M2V2 = M1V + M2V. 1000*25 + 2000*15i = 1000V + 2000V, 25,000 + 30,000i = 3000V, Divide by 1,000: 25 + 30i = 3V, V = 13m/s[50.2o] N. of E.

*November 27, 2016*

**Physics**

Correction: F = -1250 N.

*November 27, 2016*

**Physics**

V^2 = Vo^2 + 2a*d = 200^2. 300^2 + 2a*0.2 = 40,000, 0.4a = 40,000-90,000 = -50,000, a = -125,000 m/s^2. F = M*a = 0.01 * (-125000) = -11250 N. Resisting the bullet.

*November 27, 2016*

**Physics , static fluids**

Di/Dw = (920kg/m^3)/(1000kg/m^3) = 0.92 = 92% below the surface. 1.0-0.92 = 0.08 = 8% exposed.

*November 26, 2016*

**Physics**

F = 15 N.?. F = M*a, a = F/M = 15/14 = 1.07 m/s^2. V = Vo + a*t = 0 + 1,07*8 = 8.56 m/s.

*November 25, 2016*

**Physics**

Fr = 50N.[0o] + 30[30o]. X = 50 + 30*Cos30 = 76.0 N. Y = 30*sin50 = 15 N. Tan A = Y/X = 15/76 = 0.19737. A = 11.2o Fr = X/Cos A = 76/Cos11.2 = 77.5 N.]11.2o] N. of E.

*November 25, 2016*

**physics**

See previous post.

*November 24, 2016*

**physics**

M*g = 20 * 9.8 = 196 N. = Wt. of body. Fp = 196*sin30 = 98 N. = Force parallel to the incline. Fp-40 = M*a. 98-40 = M*a, a = 58/M = 58/20 = 2.9 m/s^2.

*November 24, 2016*

**Physics**

V = Vo + a*t = 2.0 rad/s. 0 + a*1.96 = 2.0, a = 1.02 rad/s^2. d = 0.5a*t^2 = 0.51*1.96*2 = 1.96 rad. (360deg./6.28rad) * 1.96rad = 112.4 deg. .

*November 24, 2016*

**Maths Ratio and Proportion**

Q1. (10/5)875 + (5/7)875 = 2375.

*November 24, 2016*