# Posts by Henry

Total # Posts: 13,448

**Algebra**

Eq1: 3x-3y+6z = 15 Eq2:-3x-6y+3z = -3(times-3). sum: =9y+9z = -18, y + z = -2. Eq2: -5x-10y+5z = -55(times-5). Eq3: +5x-8y+13z = 19 Sum: -18y+18z =-36, y - z = 2. y + z = -2. y - z = +2. Sum: 2y = 0, y = 0. z = -2. Eq1: 3x-3y+6z = 15. 3x - 3*0 + 6(-2) = 15, 3x = 27, x = 9. ...

**science**

2. Their forces are equal and opposite. 3. Unbalanced forced.

**physical sci**

Water vapor.

**math**

2005, Jamal: 21 + 3 = 24 yrs. old. a. 2005, Malcolm: 24/3 = 8 yrs. old. b. 8-3 = 5 yrs. old.

**physics**

k = (M2-M1)/(L2-L1) = (30-20)/(16-14) = 5 g/cm. d = 20g * 1cm/5g = 4cm = Distance stretched. Lu = 14-4 = 10cm = Un-stretched length.

**Math**

A. 50gal/Load * 52Loads = 2600 Gal. = 347.6 Ft^3. Cost = 347.6Ft^3 * 7.64/100 = B. (17.2/7.48)FT^3/day * 365days = 839.3 Ft^3. Cost = 839.3Ft^3 * 7.64/100Ft^3 =

**physics**

Incomplete.

**Math**

24/4 = 6 meals/day.

**maths**

d = 24*(T+5/60) = 1.25*24*(T-4/60). 24T + 2 = 30T - 2, T = 4/6 = 2/3 h. d = 24*(2/3+5/60) = ?.

**MATH**

Correction:314/(314+211+197+2243+279+325) = 0.20 Quota = 0.20 * 64 = 12.81.

**MATH**

Quota = 314/(314+211+197+243+279+325) = 12.81.

**math**

Incomplete.

**math**

I = Po*r*t = 6400*(0.0853/360)*40 = $60.66. Effective rate = (60.66/6400) * 100% = 0.95%.

**Trigonometry**

This is a rt. triangle: A = 0.5b*h = 0.5*6*8 = 24 Ft^2.

**Trigonometry**

Tan 57.68 = 50/D. D = ?.

**Trigonometry**

Tan =

**Trigonometry**

Y = 67 in. X = 67/2 = 33.5 in. Tan A = Y/X = 67/33.5 = 2.0 A = 63.43o.

**Math**

F = 700*SIN15 = 181.2 Lbs.

**Math**

a/sin A = b/sin B. a/sin43 = 10/sin112, a = ?.

**Math**

V1 = V2*1.42, V1 = (V1-20)*1.42, V1 = 67.7 Mi/h. d = V1*T1 = 67.7mi/h * 1h = 67.7 m1.

**Math**

d = V1*T1 = V2*T2. V1 * 1 = V2*(60+25)/60, V1 = V2*1.4

**science**

M1*d1 = M2*d2. M2 = 40 * 2 = M2 * 3.2, M2 = 25kg = Girl's wt.

**Physical Science**

P = I^2 * R.

**Geometry**

Find AX in the diagram if CX bisects angle ACB. And then there's a diagram below with triangle ABC, where X is on line C, BC=45, AC=21, and BX=30.

**MAth**

Disregard the first 2 lines.

**MAth**

Absent: X days. Worked: 28-x days. $9100/($500/day) =

**science**

Ans: C.

**algebra 2**

I1 = 10^6. I2 = 10^2*10^6 = 10^8. db(increase) = 10*Log(I2/I1). db(increase) = 10*Log(10^8/10^6) = 20.

**physics**

2c. Correction: 0 = 20^2 - 10d, d = 40 m.

**physics**

1. 72km/h = 72000m/3600s = 20 m/s. 2a. V2 = V1 + a*t. 0 = 20 + a*4, a = -5 m/s^2 = deceleration. 2b. F = M*a = 1200 * (-5) = -6000 N. The negative sign means the force opposes the motion. 2c. V2^2 = V1^2 + 2a*d. 0 = 20 - 10d, d = 2m.

**Math and science**

On the moon : M*g = 300 N. M*(9.8/6) = 300, M * 1.63 = 300, M = 183.7kg. On earth: Wt. = M*g = 183.7 * 9.8 = Or, On earth: 6 * 300 = 1800 N.

**mechanical principle**

Circumference = pi*d = 3.14 * 0.4 = 1.26 m. 1. Va = 8rev/20s * 6.28rad/rev = 2.51 rad/s. 2. V = 8rev/20s * 1.26m/rev = 0.502 m/s. 3. Va = Vo + a*t. 2.51 = 0 + a*20, a = 0.126 rad/s^2. 4. V = Vo + a*t. 0.502 = 0 + a*20, a = 0.025 /s^2.

**math**

P = 2h + 2W = 2*5.5 + 2*1.5 =

**Mathematics-Geomeotry PLEASE HELPPPPPP!!!!!!!**

AL = 2(W*h) + 2(L*h) = 624cm^2. 2(13*13) + 2(L*13) = 624, 338 + 26L = 624, L = 11 m. 1. Assuming the ends are square, W = h = 13 m. As = 2(L*W) + 2(L*h) + 2(W*h). 2. V = L*W*h.

**Mathematics-Geomeotry PLEASE HELPPPPPP!!!!!!!**

Correction: 1. As = 2(L*W) + 2(L*h) + 2(W*h).

**Mathematics-Geomeotry PLEASE HELPPPPPP!!!!!!!**

AL = 2(L*h) = 624cm^2. 2(L*13) = 624, L = 24cm. Assuming the ends are square, W = h = 13 cm. 1. As = 2(L*W) + AL. Or As = 2(L*W) + 2(L*h). 2. V = L*W*h.

**math**

P = Po + Po*r*t. P = 10,000 + 10,0000*(0.0825/365)*197 = 10,000 + 445.27 = $10,445.27. 3rd Payment = 10,445.27 - 6000 = $4,445.27.

**Physics**

NOTE: My vol. calculation was not required.

**Physics**

Vb = L*W*h = 12 * 12 * 6 = 864 cm^3. = Vol. of the block. Db/Dw * h = 600/1000 * 6cm = 3.6 cm submerged.

**Math**

b. 214 Ft. needed.

**Math**

a. L = 26 + 2*15 = 56 Ft. W = 21 + 2*15 = 51 Ft. P = 2L + 2W = 2*56 + 2*51 = 214 Ft. = Perimeter. Answer: 56ft by 51ft, 214ft.

**PHYSICS**

A. V = Vo + g*Tr. 0 = 40 - 9.8Tr, Tr = 4.08s = Rise time or time to reach max. ht. B. hmax = ho + Vo*Tr + 0.5g*Tr^2. hmax = 70 + 40*4.08 - 4.9*(4.08)^2 = 151.7 m. above gnd. C. Tf = Tr = 4.08 s. = Fall time. D. V = Vo + g*Tf = 0 + 9.8*4.08 = 40 m/s. E. h = ho - 0.5g*Tf^2. 0 = ...

**Math 11**

Y = a(x-h)^2 + k. 8 = a(6-5)^2 - 1, 8 = a - 1, a = 9. Y = 9(x-5)^2 - 1.

**Physics**

Correction: a. M = D*V = 6.5g/cm^3 * (20cm)^3 = 52,000g = 52kg.

**Physics**

So, the actual density is 6.5 times density of water: D = 6.5 * 1g/cm^3 = 6.5g/cm^3. a. M = D*V = 0.5g/cm^3 * (20cm)^3 = 4000g = 4kg. b. M = D*V. V = M/D = 3000g/(6.5g/cm^3) = 462 cm^3.

**Physics**

Vo = 1000/500 * 100 = 200 Volts. Po = Vo*Io = 200 * 4 = 800 Watts.

**Physics**

Ps = Pp = 120 * 0.1 = 12 Watts.

**physics**

See previous post: Mon, 4-10-17, 1:07 PM.

**physics**

Fb = M*g = 0.5 * 9.8 = 4.9 N. = Force of block. d = 4.9N/800N * 1m = 0.006125 m. = 0.6125 cm.

**physics**

Radios and TV sets often use step-up transformers to increase the 120-volt line voltage. Step-up and step-down transformers are also used for impedance matching for maximum power transfer. For example, a step-down transformer would be used to match a high resistance source to ...

**physics**

The output voltage of a step-up transformer is greater than the input voltage. The output voltage of a step-down transformer is less than the input voltage. In each case, the input voltage is connected across the primary winding, and the output voltage is measured across the ...

**physics**

Do/Dw = 0.75. Do/1 = 0.75, Do = 0.75g/cm^3 = Density of the object. M*g = 48 N. M = 48/g = 48/9.8 = 4.90 kg. = 4900g = Wt. of object. Vo = 4900g/(0.75g/cm^3) = 6533.3 cm^3 = Vol. of object. 0.75 * 6533.3 = 4900 cm^3 immersed = Vol. of water displaced. 4900cm^3 * 1g/cm^3 = ...

**PHYSICS HELP**

b. V^2 = Vo^2 + 2g*hmax. 29^2 = 0 + 19.6*hmax, hmax = 42.9 m. = Max. ht. above gnd. ho + h1 = hmax. 31 + h1 = 42.9, h1 = 11.9 m. above the cliff. a. V^2 = Vo^2 + 2g*h1. 0 = Vo^2 -19.6*11.9, Vo^2 = 233.2, Vo = 15.3 m/s = Velocity at which the rock was released.

**physics**

d = r = 31.7m = Vertical distance traveled. V^2 = Vo^2 + 2g*d. V^2 = 0 + 19.6*31.7 = 621.32, V = 24.9 m/s.

**Physics**

V1 = 15m/s[45o E of N.] = 45o N. of E. V2 = 18m/s[5o N. of E.]. Vr = 15m/s[45o] + 18m/s[5o]. Vr = 15*Cos45+15*sin45 + 18*Cos5+18*sin5. Vr = (10.61+10.61i) + (17.93+1.57i) = 28.54 + 12.18i. Magnitude = sqrt(28.54^2 + 12.18^2) = Tan A = Y/X = 12.18/28.54 = 0.42887. A =

**Algebra**

My answer is B.

**physics question**

Fc = M*g = 100 * 9.8 = 980 N. a. Work/s = F*d/t = 980 * 16/20 = 784 J./s. = 784 Watts. b. Po = Work/s = 784 J/s. c. Efficiency = Po/Pi = 784Watts/1000Watts = 0.784 = 78.4%.

**physics**

a. V^2 = Vo^2 + 2a*d. 0 = 20^2 + 2a*100, a = -2 m/s^2. b. F = M*a = 1000*(-2) = -2,000 N. c. W = F*d = -2000 * 100 = -200,000 Joules.

**physics**

Idc = 2Ipk/pi. 0.6 = 2Ipk/3.14, 2Ipk = 1.88, Ipk = 0.94 mA.

**physics**

Idc = Imax/pi = (1.414*150)/3.14 = 67.5 uA.

**physic**

Imax = I1max - I2min. Imax = (79+0.03*100) - (31-0.1) = 82 - 30.9 = 51.1 mA. Imin = I1min - I2max. Imin = (79-0.03*100) - (31+0.1) = 76 - 31.1 = 44.9 mA.

**Maths**

F(x) = (4x+7) + (x^2-2x). F(x) = Y = x^2 + 2x + 7. X = -B/2A = -2/2 = -1. Y = (-1)^2 + 2(-1) + 7 = 6. Min. point: (x,y) = (-1,6).

**Math**

2nd side = X yds. 1st. side = x-5 yds. 3rd. side = (x-5)-2 = x-7 yds. X + (X-5) + (X-7) = 42. 3x - 12 = 42, X = 18 Yds. X-5 = 18-5 = 13 Yds. X- 7 = 18 - 7 = 11 Yds.

**Math, slope**

C = 5 + 0.75/0.5KM. C = 5 + 1.50/km Eq: C = 1.5x + 5. C = Cost. Slope = 1.5. X = Distance traveled. Y-Intercept = 5.

**Calculus**

Tan(A) = Y/X = -7/2 r^2 = X^2 + Y^2 = 2^2 + (-7)^2 = 53, r = sqrt(53). a. sin(A) = Y/r = (-7)/sqrt(53) = (-7)*sqrt(53)/53. b. Cos(A) = X/r = 2/sqrt(53) = 2*sqrt(53)/53. c. sec(A) = 1/Cos(A) = qrt(53)/2. d. csc(A) = sqrt(53)/(-7). e. cot(A) = 1/Tan(A) = 2//(-7). = - 2/7.

**Calculus**

V^2 = Vo^2 = 2a*d. 0 = Vo^2 - 32*200, Vo^2 = 6400, Vo = 80 Ft/s. Vo = 80FT/s * 1m1/5280Ft. * 3600s/h = 54.5 mi/h. = Initial velocity.

**Physics 12**

a. Fr = F1 + F2 = 360 + 360 = 720 N. b. Fr = 360[0o] + 360[60o]. Fr = 360 + (180+312i) = 540 + 312i = 624N.[30o]. c. Fr = 360[0o] + 360[120o]. Fr = 360 + (-180+312i) = 180 + 312i = 360N.[60o]. d. Fr = 360[0o] + 360[180o]. Fr = 360 + (-360+0l) = 0.

**algebra**

Incomplete.

**physics**

V^2 = Vo^2 + 2a*d. 1.12^2 = 0 + 2a*5.4, a = 0.116 m/s^2. M*g = 6.8*9.8 = 66.64 N. = Wt. of bats. = Normal force(Fn). Fk = u*Fn = 66.64u. Fe-Fk = M*a. 20-66.64u = 6.8*0.116 = 0.789, 66.64u = 20-0.789 = 19.2, u = 0.288.

**math**

u(8,-3), v(-3,-8). Tan A = (-8-(-3))/(-3-8) = -5/-11 = 0.45455, A = 24.4o. S. of W.

**mechanics**

M*a = -30. a = -30/M = -30/0.54 = -55.6 M/S^2. V = Vo + a*t = 15 - 55.6*0.25 = 1.11 m/s.

**mechanics**

V = Vo + a*t. 12 = 15 + a*0.25, a = -12 m/s^2. a. Fe = M*a = 1200*(-12). b. M1*V1 + M2*V2 = M1*V3 + M2*V4. 1200*15 + 800*10 = 1200*12 + 800V4, 18,000 + 8000 = 14,400 + 800V4, -14,400 + 26,000 = 800V4, 800V4 = 11,600, V4 = 14.5 m/s. = Velocity of the car.

**Phyisics**

Vs = Vo + 0.6m/s/Co. Vs = 340 + 0.6*127 = 416 m/s.

**math**

1. S = 5000. 2. S = 5000 + 1500 = 6500. 3. S = 6500 + 1500 = 8,000. 4. S = 8000 + 1500 = 9,500. S = 5000 + 5000*0.3*(n-1). Factor out 5000: Eq: S = 5000(1 + 0.3*(n-1)). 2. S = 5000(1+0.3*(2-1)) = 6500. 3. S = 5000(1+0.3*(3-1)) = 8000. 4. S = 5000(1+0.3*(4-1)) = 9500.

**Physics**

1-0.8 = 0.2 N. lost. M*g = 0.2, M = 0.2/9.8 = 0.0204 kg = 20.4 grams lost

**Math Fractions**

6cups * 8oz/cup = 48 oz. of sports drink concentrate. 48oz + 9*48oz. = 480 oz. 480oz./(128oz/gal) = 3.75 Gal.

**Math**

P = (Po*r*t)/(1-(1+r)^-t). Po = $20,300. r = 0.0975/12 = 0.008125/mo. t = 4yrs. * 12mo./yr. = 48 mo. P = (20,300*0.008125*48)/(1-1.008125^-48). P = 7917/(1-1.008125^(-48)), P = 7917/0.32187535 = $24,596.48. M.P. = P/48. = 24,596.48/48 = $512.43.

**Physics**

A. V2^2 = V1^2 + 2g*h. V2^2 = 0 + 19.6*1.25 = 24.5, V2 = 4.95 m/s.

**physics**

Avg. Speed = (20+60+120)/3 = 66.67 km/h.

**physical sciences**

V2 = a*t = 4 * 40 = 160 m/s = Take-off speed. V2 = V1 + a*t. 160 = V1 + 4*40, V1 = 0.

**Physics**

Vr = 25 + 100i = 103m/s[76o].

**Physics**

output = 0.8 * Input =

**Physics**

V1 = 610rev/min * 6.28rad/rev * 1min/60s = 63.85 rad/s. V2 = V1 + a*t. = 63.85 + 5.9*3.2 = 82.73 m/s.

**Math**

kids ticket = $X each. Adult tickets = $2X each. 9x + 2*2x = 72. X = ?.

**math**

Width = X ft. Length = 2x+3 Ft. A = L*W = (2x+3)x = 65. 2x^2+3x = 65, 2x^2 + 3x - 65 = 0, Use Quadratic Formula: X = (-3 +- sqrt(9 + 520))/4 X = (-3 +- 23)/4 = 5, and -6.5. X = 5 Ft. = Width. Length = 2*5 + 3 = 13 Ft. P = 2L + 2W.

**physics**

F = M*g = 0.50 * 9.8 = 4.9 N. X = (1m/175N)*4.9N. + (1m/270N)*4.9N = 0.028 + 0.0181 = 0.0461 m.

**Physicd**

a. Fap = M*a. 10 = 2a, a = 5 m/s^2. b. V = Vo + a*t = 10 + 5*5 = 35 m/s.

**MATH**

d = 15mi/h*(40/60)h + 10mi/h*(20/60)h = 13.33 miles. - Total dist. traveled. r = 13.33mi/1h = 13.33 mi/h.

**5th grade math equation**

3 + 6*(5+4/2)-7 = 38.

**physics**

V^2 = Vo^2 + 2g*h. V = 0, Vo = 10 m/s, g = -9.8 m/s^2, h = ?.

**Physics**

M*g = 85*9.8 = 833 N. = Force of load. Effort = 833/0.85 =

**eec115 electrical and electronic engineering science**

C1 = 10uF, C2 = 5uF. C = C1*C2/(C1+C2) = (10*5)/(10+5) = 3.33 uF. a. Q1 = Q2 = C*V = 3.33 * 20 = 66.6 Micro Coulombs. b. V1 + V2 = 20 V2 = 10uF/5uF * V1 = 2V1, V1 + 2V1 = 20, V1 = 6.66 Volts.

**Pre-calculus**

Disp. = 4km[30o] + 10km[160o]. X = 4*Cos30 + 10*Cos160 = -5.93km. Y = 4*sin30 + 10*sin160 = 5.42km. Tan A = Y/X = 5.42/(-5.93) = -0.91403, A = -42.43o N. of W.137.6o CCW from + x-axis. Disp. = X/Cos A = (-5.93)/Cos137.6 = 8.03 km[137.6]

**Physics - Voltage across a wire of unknown length**

p = 1.68*10^-8 Ohm m = 1.68*10^-6 Ohm cm. R1 = pL/A = (1.68*10^-6)L/1cm^2 = (1.68*10^-6)L Ohm. R2 = (1.68*10^-6)L/2cm^2 = (0.84*10^-6)L Ohm. R3 = (0.56*10^-6)L Ohm. R4 = (0.42*10^-6)L Ohms. R = R1 + R2 + R3 + R4. R = (1.68L+0.84L+0.56L+0.42L)10^-6 = (3.5*10^-6)L Ohms. I = E/R...

**Algebra**

P = Po*e^(r*t). r*t = 0.05*6 = 0.3. P = 1200 * e^0.3 = $1619.83.

**Business Math**

P = (Po*r*t)/(1-(1+r)^-t). Po = 0.7*200,000 = 140,000. r = 0.115/12 = 0.009583/mo. = Monthly % rate. t = 30yrs. * 12mo./yr. = 360 mo. P = (140,000*0.009583*360)/(1-(1.009583)^-360) = 499,091.50. M.P. = P/360.

**physics**

Circumference = pi*D = 3.14 * 150 = 471.2 m. V = 471.2m/30min * 1min/60s = m/s.

**Maths**

P = Po + Po*r*t. P = $24,200, r = 0.07, t = 3 yrs. Po = ?.

**Physics 2**

T1 = 20oC. T2 = 140oC. D = Do + Do*a*(T2-T1) Density = 19.3 + 19.3*14.3*10^-6/oC*(140-20)oC = 19.333 g/cm^3.

**Physics**

M*g = 10 * 9.8 = 98 N. = Wt. of mass. The system is in equilibrium: T1*Cos60 = -T2. T1 = -T2/Cos60 = -2T2. T1*sin60 = 98 N. T1 = 98/sin60 = 113.2 N. -2T2 = T1 = 113.2, T2 = -56.6 N. = Tension in horizontal string.