# Posts by henry

Total # Posts: 13,338

**science**

V = Vo + a*t = 0.8 m/s. Vo = 0, t = 2 s. a = ?.

*January 27, 2016*

**Algebra**

Angle #1 = X Deg. Angle #2 = X Deg. Angle #3 = (X+9) Deg. x + x + x+9 = 180 Deg. 3x = 171. X = 57o x+9 = 57+9 = 66o = Largest angle.

*January 27, 2016*

**physics**

Wb = M*g = 15 * 9.8 = 147 N. Fn = 147 - 55*sin32 = 117.9 N. = Normal force. Fk = u*Fn = 0.25 * 117.9 = 29.5 N. = Force of kinetic friction. Work = (55*Cos32-29.5) * 15 = 257 Joules.

*January 27, 2016*

**Math**

k = 12Lbs/9in = 1.33 Lbs/in.

*January 27, 2016*

**Physics**

F = M*a = -7540 N. a = -7540/M = -7540/2700 = -2.79 m/s^2. V = Vo + a*t, V = 29.8 - 2.79*2.77 = 22.1 m/s.

*January 27, 2016*

**Physics**

V^2 = Vo^2 + 2g*h. V = 0, g = -9.8 m/s^2, h = 500 m. Vo = ?.

*January 27, 2016*

**math**

Fist book cost $X. 2nd book cost (3x+4) Dollars. x + 3x+4 = 72. X = ?

*January 27, 2016*

**physics**

If the capacitors are connected in series, C1*V1 = 150 uC, V1 = 150/C1 = 150/3 = 50 Volts. 120-50 = 70 Volts across other two capacitors.

*January 26, 2016*

**Physics**

3. M*V1 + M*V2 = M*V3 + M*V4. M*2.1 - M*3 = -M*3 + M*V4. V4 = ? 4. M1*V1 + M2*V2 = M1*V + M2*V. 1800*22i + 3200*14 = 1800V + 3200V. Divide both sides by 100 and solve for v.

*January 26, 2016*

**Physics**

1. M1 = M2 = M. Unless otherwise stated, all angles are measured CCW from +x-axis. M*V1 + M*V2 = M*V3 + M*V4. M*0 + M*V2 = M*0.92m/s[161o] + M*1.25m/s[46o]. M*V2 = 0.92M[161o] + 1.25M[46o]. Divide both sides by M and solve for V2 V2 = -0.87+0.30i + 0.87+0.90i = 1.20i = 1.20m/s...

*January 26, 2016*

**physics**

a. L = V/F = 5.1*10^-3. V/(2.8*10^5) = 5.1*10^-3. V = m/s. b. d = V*t; t = d/V = 3000/V.

*January 25, 2016*

**physics**

t = 21/5.6

*January 25, 2016*

**physics**

a. h = 0.5*g*t^2 = 0.4 m. g = 9.8 m/s^2. t = ?

*January 25, 2016*

**Physics**

d. d = Xo*T = 25m/s * 3s. = 75 m. e. Tr = 3s/2 = 1.50 s. = Rise time. e. Y = Yo + g*Tr = 0. Yo - 9.8*1.5 = 0. Yo = 14.7 m/s = Ver. component of initial velocity. f. Tan A = Yo/Xo = 14.7/25 = 0.58800. A = 30.5o.

*January 25, 2016*

**Physics**

h = 0.5g*t^2 = 1.52

*January 25, 2016*

**Physics**

V^2 = Vo^2 + 2g*h = 0 +19.6*1.25 = 24.5 V = 4.95 m/s. V(avg) = (Vo+V)/2 = (0+4.95)/2 = 2.47 m/s.

*January 25, 2016*

**physics**

Wc = M*g = 100kg * 9.8N/kg = 980 N. = Normal(Fn). Fap-Fk = M*a. 450-u*980 = M*0 = 0. -980u = -450. u = 0.459

*January 25, 2016*

**physics**

See previous post: Sun, 1-24-16, 10:49PM.

*January 24, 2016*

**physics**

d = r*t = 4.8*10^6m. 300*t = 4.8*10^6 t = 16,000 s. = 4.44 h.

*January 24, 2016*

**Physics**

X = 580 km/h = Velocity of airplane. Y = 92 km/h = Velocity of wind. Tan A = Y/X = 92/580 = 0.15862 A = 9.0o N. of E. Speed = Sqrt(X^2+Y^2) = km/h. Since the wind is northward, the direction is N. of E. NOT S. of E.

*January 24, 2016*

**Electronics Engineering Technology**

dbm = 10*Log(Po/Pi) = 10. 10*Log(Po/1) = 10. Log(Po/1) = 1.0. Po/1 = 10^1 = 10. Po = 10 mW = Power output of driver to transmitter. Po = Vo^2/R = 10 mW = 0.01 W. Vo^2/600 = 0.01 Vo^2 = 6. Vo = 2.45 Volts across 600 Ohms.

*January 24, 2016*

**math**

(7,5), (8,7), (x,11). Slope = (7-5)/(8-7) = 2. Slope = (11-7)/(x-8) = 2. 2x-16 = 4. X = 10.

*January 24, 2016*

**physics**

d = 0.5a*t^2.

*January 24, 2016*

**PHYSICS**

Vo = 50mi/h = 22.22 m/s. Wt. = 3000Lbs = 1362 kg. d = 200Ft = 60.61 m. a = -Vo^2/2d = -(22.22^2)/121.2 = -4.07 m/s. Fb = M*a = 1362 * (-4.07) = -5543 N. = Braking force. V = Vo + a*t = 0. t = -Vo/a = -22.22/-4.07 = 5.45 s. = Time required to stop.

*January 23, 2016*

**PHYSICS**

Mass = 1420Lbs * 0.454kg/Lb. = kg Wt. = M*g = 412kg * 9.8N/kg = Newtons.

*January 23, 2016*

**Science**

d = 0.5a*t^2.

*January 23, 2016*

**Algebra 2**

3a. V^2 = Vo^2 + 2g*h = 0. h = -Vo^2/2g + 70 = 422 Ft = Ht. above gnd. V = Vo + g*Tr = 0. 150 - 32*Tr = 0. 32Tr = 150. Tr = 4.7 s. = Rise time or time to reach max. ht. b. h = 0.5g*Tf^2 = 422. 16Tf^2 = 422. Tf^2 = 26.375. Tf = 5.14 s. = Fall time. Tr+Tf = 4.7 + 5.14 = 9.84 s...

*January 22, 2016*

**science**

(T-20)oC * 25*10^-6m/oC = 10^-3m. 25*10^-6T - 5*10^-4 = 10^-3 25*10^-6T = 1.5*10^-3 T = 0.06*10^3 = 60 oC.

*January 22, 2016*

**Science**

d = V*T = 8.66*10^7km = 8.66*10^10 m. 3*10^8 * T = 8.66*10^10.

*January 21, 2016*

**ALgebra**

X = $10-coins. 54-x = $20-coins. 10x + 20(54-x) = 780. 10x + 1080 - 20x = 780. -10x = -300. X = 30. 54-x = 54-30 = 24

*January 21, 2016*

**Math**

Do you mean V = (128/9)pi? V = pi*r^2*h = (128/9)pi. 3.14*r^2*8 = 44.7 r^2 = 1.78 r = 1.33 In. D = 2r = 2.7 In.

*January 21, 2016*

**Math**

4m * 100cm/m = 400 cm. 4m + 20cm = 400cm + 20cm = 420 cm.

*January 21, 2016*

**physics**

X = 8.30 m. Y = 7.00 m. Tan A = Y/X = 7.00/8.30 = 0.84337

*January 21, 2016*

**math**

As = 2pir^2 + 2pi*r*h = 6.28*2^2 + 6.28*2*9 = 138.2 In^2. 138.2In^2 * 1Ft^2/144In^2 = 0.959 Ft^2. 0.959Ft^2/box * 1500boxes = 1439.2 Ft^2. of cardboard.

*January 21, 2016*

**Math**

1/(1/4) * 1/2 = 1*4/1 * 1/2 = 2 Cups of apple juice.

*January 20, 2016*

**Math**

Width = W cm. Length = W+8 cm. 2W + 2(W+8) = 84 cm W = ?.

*January 20, 2016*

**Business Math**

Correction: Change 0.04 to 0.044.

*January 20, 2016*

**Business Math**

Check: I counted 213 days. I = Po*r*t = 760*(0.04/365)*213 =

*January 20, 2016*

**Math**

A. (1/2)/(1/4) = 1/2 * 4/1 = 2 Batches of brownies. A. (4 4/5)/(2/5) = (24/5)/(2/5) = 24/5 * 5/2=120/10=12 Two-fifth pieces of rope. B. So their are 12 two-fifths in four and four-fifth. (32 1/4)/(1/8) = 258. A. B. 32 1/4 * 8 or 129/4 * 8. C. There are 258 one-eights in 32 1/4...

*January 20, 2016*

**math**

Ordinary Interest Ar = Ab - Ab*r*t. Ar = 500 - 500*(0.09/360)*82 = Amount received or Discounted value. Ar = 1000 - 1000*(0.15/360)*55 = Amount received or Discounted value.

*January 20, 2016*

**math**

Cost = (13.98+3.96)/6 =

*January 19, 2016*

**Math**

Ap=L*W = 100cm * 20cm=2000 cm^2 = Area of the paper. As = 2(W*h) + 2(L*h) + 2(L*W) = Surface area box. As=2(15*15) + 2(15*15) + 2(15*15) = 6(15^2) = 1350 cm^2. Ap-As = 2000 - 1350 = 650 cm^2 Left.

*January 19, 2016*

**math**

width = W Feet. Length = 2W+4 Feet. A = (2W+4)*W. (2W+4)*W = 100.

*January 19, 2016*

**Math**

X dimes. 81-x nickels. 0.1x + 0.05(81-x) = 5.75 Multiply both sides by 100: 10x + 5(81-x) = 575. x = ?

*January 19, 2016*

**algebra**

-9m^-2*n^5*2m^-3*n^-6 = -18m^-5*n^-1 = -18/m^5*n. Answer: B.

*January 19, 2016*

**algebra**

Day 1. x miles. 2. 3x+52 miles. 3. x-83 miles. D = x + 3x+52 + x-83 = 5x - 31.

*January 19, 2016*

**how to set this up**

See previous post: Tue, 1-19-2016, 1:56 PM .

*January 19, 2016*

**8th grade Algebra**

49z^4-25y^4=(7z^2+5y^2)(7z^2-5y^2).

*January 19, 2016*

**i dont know how to solve this**

History: 0.93 = 93%.

*January 19, 2016*

**i dont know how to solve this**

English: (13/14)*100% = 92.9% Science: 93%. Math: (25/27)*100% = History: 9.93 = 93%.

*January 19, 2016*

**how to set up this problem**

Bal.=Ao - ((1/3)Ao+17.11+26.74) = Ao = $75 = Initial amount.

*January 19, 2016*

**math**

I = Po*r*t = $20. 325*(r/12)*2 = 20. 325*r/6 = 20. 325r = 120. r = 0.369 = 36.9% APR.

*January 19, 2016*

**Math**

P = Po(1+r)^n. r = (0.05/12)*1/2 = 0.0020833 = Semi-monthly % rate. n = 2Comp/mo. * 300mo = 600 Compounding periods. Solve for P. I = P-Po.

*January 19, 2016*

**Math**

P = Po + Po*r*t = 10,000. Po + Po*(0.04/52)*13 = 10,000. Po + 0.01Po = 10,000. 1.01Po = 10,000. Po = $9900.99

*January 19, 2016*

**Math**

P = Po(1+r)^n = 2M. Po(1.04)^35 = 2. 3.94609Po = 2. Po = 0.50683M. = $506,830.

*January 18, 2016*

**math**

P = Po(1+r)^n. r = (7%/12)/100% = 0.005833 = Monthly % rate expressed as a decimal. n = 12Comp/yr. * 1.5yrs. = 18 Compounding periods. P = 7000(1.005833)^18 = $7737.90. APY = ((P-Po)/Po)*100 =

*January 15, 2016*

**Math**

2. Given: P(0,5), m = 1/2. Y = mx + b = 5. (1/2)*0 + b = 5, b = 5. Eq: Y = (1/2)x + 5. 3. Given: (1,2), (2,3). m = (3-2)/(2-1) = 1/1 = 1. Y = mx + b = 2. 1*1 + b = 2, b = 1. Eq: Y = x + 1. 8. Same procedure as #3. 9. Given: (2,3), (x,y), m = -2. m = (y-3)/(x-2) = -2. Cross ...

*January 15, 2016*

**Math**

Y = (2/3)x + 2 x = 0 at the point where the graph crosses the y-axis. So in the Eq above, replace x with 0 and solve for y: Y = (2/3)*0 * 2 = 0 + 2 = 2. (x,y) = (0,2).

*January 15, 2016*

**Math**

P = 1,092 - (1/3+2/7)*1,092 = 1,092 - (7/21+6/21)*1092 = 1092 - (13/21)*1092 = 1092 - 676 = 416.

*January 15, 2016*

**physics**

Fap-Fk = M*a 550.27-Fk = M*0 = 0. Fk = 550.27 N.

*January 15, 2016*

**ECE**

Vb-a = 3 + 2 = 5 Volts. Va-b = -2 + -3 = -5 Volts. If the problem asked for Vb-a, I would say, +5 volts. If it asked for Va-b, I would say negative 5 volts. But it didn't ask for neither of the above; therefore, my answer would be "Five volts".

*January 15, 2016*

**Physics**

Vo = 1.67m/s[30o]. Yo = 1.67*sin30 = 0.835 m/s. Y = Yo + g*t = 0. 0.835 - 9.8*t = 0. 9.8t = 0.835. t = 0.0852 s. = 8.52*10^-2 s.

*January 15, 2016*

**Physics**

Fm = M*g=40kg * 9.8N/kg = 392 N. = Force of the mass. T1*Cos25 = -T2. T2 = -T1*Cos25 = -0.91T1. T1*sin25 = 392. T1 = 928 N. T2 = -0.91*T1 = -0.91 * 928 = -841 N.

*January 14, 2016*

**Maths**

a. 17/20 b. (17/20) * 100% =

*January 14, 2016*

**Maths**

4.39

*January 14, 2016*

**Maths**

5.078, 5.08, 5.287, 5.78, 5.8

*January 14, 2016*

**Math**

1. Friend's lunch = F. Your lunch = F+3. f + f+3 = 19. 2. Jason's wt. = 36 Lbs. His sister's wt. = w Lbs. w + 36 = 3w+4. 3. X packages sold last year. 35 = 2x-1. 4. 10 + x = 70. 5. 60 + x > 200. 6. 6.25h >= 143.75. your

*January 12, 2016*

**math help**

20 - 5 - 0.75x = 0. 20-5-0.75x = 0. 0.75x = 15. X = 20 Tickets.

*January 12, 2016*

**Algebra**

1. (3,8), (9,5). m = (5-8)/(9-3) = 2. (-7/2,-3), (-5,5/2). m = (5/2-(-3))/(-5-(-7/2)) = (5/2+6/2)/(-10/2+7/2) = (11/2)/(-3/2) = 11/2 * (-2/3) = -22/6. 3. (8,3), (x,y), m = 5. m = (y-3)/(x-8) = 5. Cross multiply: y-3 = 5(x-8).

*January 12, 2016*

**Algebra**

5k - 2k + 4k + 0.005k = 7.005k.

*January 11, 2016*

**math**

x^3 = 3.85*10^-17. Take the cube root of both sides by raising it to the 1/3 power: (X^3)^(1/3)=(3.85*10^-17)^(1/3). X = 3.38*10^-6.

*January 11, 2016*

**Trigonometry**

h/38 = 0.34/0.69

*January 11, 2016*

**Math**

42 < -6d. -7 > d. or d < -7.

*January 11, 2016*

**physics**

a = (V-Vo)/t. Initial Momentum = M*Vo. Final momentum = M*V. Change in momentum = M*V-M*Vo. F = M*a.

*January 11, 2016*

**Math**

See previous post.

*January 11, 2016*

**Math**

Multiply Eq1 by -2 and add: Eq1: -3x - 4y = -22. Eq2: +3x + 6y = 22. Sum: 2y = 0. Y = 0. In Eq2, replace y with 0 and solve for x: 3x + 6*0 = 22. X = 7 1/3. One solution.

*January 11, 2016*

**Math Check (thanks)**

1. 6/(4*5) = 6/20 = 3/10 = 30%. 3. 19/25 = 0.76 = 76%. 4. 0.09 * 100% = 9%. 5. 37.1%/100% = 0.371. 6. 0.8 = 80%; 7/8 = 87.5%. 19/25 = 0.76 = 76%. Order: 19/25, 0.8, 81%, 7/8. 7. (165/250) * 100% = 8. (4/15) * 100% = 9. (52/5) * 100% = 10. 365%/100% = 3.65 = 3 13/20. 11. 100...

*January 11, 2016*

**Math**

A semicircular shape is in a (fills it) rectangle. If the perimeter of the rectangle is 30 cm, fine the perimeter of the semicircular shape.

*January 11, 2016*

**Algerbra**

y + 4x = 3. y + 4*(-1) = 3. Y = 7. (-1,7). y + 4*5 = 3. Y = -17. (5,-17).

*January 10, 2016*

**Physics**

Vo = 100m/s[30o]. Yo = 100*sin30 = 50 m/s. Y^2 = Yo^2 + 2g*h. h = (Y^2-Yo^2)/2g + ho. y = 0. g = -9.8 m/s^2. ho = 100 m. h = ?

*January 10, 2016*

**math**

(-6,1), (-3,2). m = (2-1)/(-3-(-6))/ = 1/3. Y = mx + b. (1/3)(-6) + b = 1. -2 + b = 1. b = 3. Y = (1/3)x + 3.

*January 10, 2016*

**maths**

T1*T2/(T1+T2) = T3. T1*(T1-10)/(T1+(T1-10)) = T1-18. (T1^2-10T1)/(2T1-10) = T1-18. Multiply by 2T1-10: T1^2-10T1 = 2T1^2-36T1-10T1+180 -T1^2 + 36T1 - 180 = 0 T1^2 - 36T1 + 180 = 0. -6*-30 = 180, -6 + -30 = -36 = B. (T1-6)(T1-30) = 0. T1-6 = 0, T1 = 6 h. T1-30 = 0, T1 = 30 ...

*January 10, 2016*

**maths**

T = Ta*Tb/(Ta+Tb) = 40*30/(40+30)= 17.14 Min. to fill with both pipes open. (17.14-5)/17.14 = 0.708 of a tank to be filled. 5 + 0.708*40 = 33.34 Min., total.

*January 10, 2016*

**Math**

400qts. = 1600 Cups. 400qts < 4000 Cups. or 4000Cups > 400qts.

*January 10, 2016*

**Math**

400qts * 32oz/qt * 1cup/8oz = 1600 Cups.

*January 10, 2016*

**Math**

X > c-b.

*January 10, 2016*

**physics**

Unless otherwise stated, all angles are measured CCW from the +x-axis. D = -120 + 210[315o] + 280[60o]. X = -120 + 210*Cos315 + 280*Cos60 = 168.5 m. Y=210*sin315 + 280*sin60 = 94 m. Tan A = Y/X = 94/168.5 = 0.55786 A = 29.2o D = X/Cos A = 168.5/Cos29.2 = 193 m[29o]. b. ...

*January 9, 2016*

**physics**

610MW = 610MJ/s. a. Energy = 610MJ/s * 3600s/h * 24h/day * 30days = 1.581*10*9 MJ.

*January 9, 2016*

**math**

I = Ab*r*t=749.25*(0.12/360)*120 = $29.97 Ar = Ab-I=749.25 - 29.97=$719.28 = Amount received(proceeds). I = Interest. Ab = Amt. borrowed. Ar = Amt. received.

*January 8, 2016*

**1 math question**

Correct.

*January 8, 2016*

**Calculus**

A water tank is made by rotating f(x)=2^x-1 between [0,2] about the y-axis. The water tank is initially full, when a hole is opened at the bottom tip so that the water drains at a rate of 4 unit^3/second. How fast is the height of the water decreasing when the height has ...

*January 8, 2016*

**Math**

2. T-((T/2)-6 + (T/3)-2) = T-((3T/6)-6 + (2T/6)-2) = T - ((5T/6) - 8) = T - 5T/6 + 8 = 6T/6 - 5T/6 + 8 = T/6 + 8.

*January 7, 2016*

**Math**

1. #1. m. #2. 2m-1. #3. 4m-2-1 = 4m-3. #4. 8m-6-1 = 8m-7. #5. 16m-14-1 = 16m-15. #6. 32m-30-1 = 32m-31. m + 2m-1 + 4m-3 + 8m-7 16m-15 + 32m-31 = 63m - 57.

*January 7, 2016*

**Physics-Conservation of Momentum**

V1 = 90km/h = 90000m /3600s = 25 m/s. V = 80km/h = 80000m/3600s = 22.2 m/s. M1*V1 + M2*V2 = M1*V + M2*V. M1*25+6000*0=M1*22.2 + 6000*22.2 25M1-22.2M1 = 6000*22.2. 2.78M1 = 133,200. M1 = 47,952 kg. = 4.8*10^4 kg.

*January 7, 2016*

**Maths**

(2/3)*3.14*(30/2)^3=3.14*r^2*22.5 7069 = 70.69r^2. r^2 = 100. r = 10 cm.

*January 7, 2016*

**Math**

1. D = 200[115o] + 150[230o]. X = 200*Cos115 + 150*Cos230 = -181 km. Y = 200*sin115 + 150*sin230 = 66.4 km. D = Sqrt(X^2 + Y^2) = Distance from C to A. Tan A=Y/X = 66.4/-181 = -0.36685 A = 20.1o N. of W. = 159.9o CCW. = Bearing.

*January 7, 2016*

**Math**

Vc = 12*18*6 = 1296 in^3. Vb = 4*6*2 = 48 in^3. Vc/Vb = 1296/48 = 27 Boxes.

*January 6, 2016*

**ALGEBRA**

9m/2 - 6 = -7/2 + 4m. Multiply both sides by 2: 9m - 12 = -7 + 8m. 9m - 8m = 12 - 7. m = 5.

*January 6, 2016*

**area perimeter**

2L + 2W = 28. Divide both sides by 2: Eq1: L + W = 14. Eq2: L*W = 24. L = 24/W. In Eq1, replace L with 24/W: 24/W + W = 14. Multiply both sides by W: W^2 + 24 = 14W. W^2 - 14W + 24 = 0. 24 = -2*-12, -2 + -12 = -14 = B. (w-2)(w-12) = 0. w-2 = 0, W = 2. w-12 = 0, W = 12. (L,W) (...

*January 6, 2016*

**Typo (Test Marked)**

1. N = 0.73 * 215 = 156.95 2. 23/94 = 0.2447 = 24.47%. 3. 80 = 0.40*N. N = 200. 4. C = 0.05 * 1250 = $62.50 5. 100% + 6% = 106% = 1.06 Total Cost = 1.06 * 325 = $344.50

*January 6, 2016*