Thursday

February 23, 2017
Total # Posts: 13,201

**physics**

Do you mean constant velocity? If so, d = V*t, t = d/V.

*February 11, 2016*

**physical science**

d = 0.5a*t^2. d = 10 m, t = 45 s, a = ?.

*February 10, 2016*

**mathematics**

David: X years old. John: x+4 years old. Joe: x-2 years old. x + x+4 + x-2 = 41. Solve for x and add 8 years to John's age.

*February 10, 2016*

**Pysics**

D = -400 + 200[135o] + 100i = -400 - 141.4+141.4i + 100i = -541.4 + 241.4i = 593 km[24o] N. of W.

*February 10, 2016*

**Science**

1. V = Vo + a*t. V = 3.2 m/s, Vo = 1.2 m/s, t = 2.5 s, a = ?. 2. V = Vo + a*t. V = 34 m/s, Vo = 0, t = 2.5 s, a = ?. d = 0.5a*t^2. 3. r = 30m/4.2s. = 4. d = r*t, t = ?.

*February 10, 2016*

**Math**

The simplification process starts inside the expression: ((3x)^4/(6x)^3)^2 = (81x^4/216x^3)^2 = (3x/8)^2 = 9x^2/64.

*February 9, 2016*

**Math**

Y = 3x. 3 = The number of wheels per tricycle. X = The number of tricycles. Y = The total number of wheels to be ordered.

*February 9, 2016*

**math**

15, 5, 3, 0.8, -5.

*February 9, 2016*

**Math**

Po*e^(rt) = 2Po. Divide both sides by Po: e^rt = 2. rt = 0.08t. e^0.08t = 2. 0.08t*Log e = Log 2. 0.08t = Log2/Log e = 0.693 t = 8.7 yrs.

*February 9, 2016*

**math**

a. Tan 24 = h/500, h = ?. b. Tan 27 = (h+L)/500. L = Length of flag = ? h = Ht. of bldg. calculated in part a.

*February 9, 2016*

**physics**

See previous post: Mon, 2-8-16, 7:33 PM.

*February 9, 2016*

**science**

30kW = 30 kJ/s. Work = 30kJ/s * 15s = 450 kJ.

*February 9, 2016*

**Calculus 2**

Sketch the region in the first quadrant enclosed by y=7/x, y=2x, and y=x/2. Decide whether to integrate with respect to x or y. Then find the area of the region.

*February 9, 2016*

**physics**

a. Vr = -100i + 70km[330o] = -100i + 60.6-35i = 60.6 - 135i = 148km[65.8o] S. of E = 24.2o E. of S. = Resultant velocity of the goose. Do you mean 20o W. of S.? If so, Direction = 24.2 + 20 = 44.2o W. of S. b. d = V*t = 1000, t = 1000/V = 1000/148 = 6.76 h.

*February 8, 2016*

**SIMPLE INTEREST**

I = Po*r*t = 5000*0.04*2 = $400. (25/4)% = 6.25%. I = 5000*0.0625*2 = $625. Gain = (625-400)/2yrs. = $112.50 per year.

*February 8, 2016*

**SIMPLE INTEREST**

I = Po*r*t = 0.125Po. Po*0.1*t = 0.125Po. t = 1.25 yrs. = 15 Months.

*February 8, 2016*

**SIMPLE INTEREST**

I = Po*r*t = 1344-1200. Po = 1200, r = 0.06, t = ?.

*February 8, 2016*

**SIMPLE INTEREST**

I = Po*r*t = 1770. r = 0.08 t = (15/2)yrs. = 7.5 yrs. Po = ?.

*February 8, 2016*

**SIMPLE INTEREST**

There are errors in your problem; please make corrections.

*February 8, 2016*

**science**

Sketch: From a point, draw 2 arrows pointing upward and one arrow pointing downward.

*February 8, 2016*

**science**

Fr = 5.3 + 2.2 - 10.7 = -3.2 N. = 3.2 N. downward.

*February 8, 2016*

**Engineering**

Mass = 0.00072kg/cm^3 * 37854cm^3/gal * 5gal. = 136.3 kg.

*February 7, 2016*

**physics**

h = V*t + 0.5g*t^2 = 2 m. V*0.1 + 4.9*0.1^2 = 2. 0.1V = 2-0.049 = 1.95. V = 19.5 m/s at top of the window. V^2 = Vo^2 + 2g*h. V = 19.5 m/s, Vo = 0, g = 9.8 m/s^2, h = ?.

*February 7, 2016*

**Finance**

P = Po(1+r)^n. P = $16,860. r = 5.75%/100 = 0.0575 n = 1Comp./yr. * 6yrs. = 6 Compounding periods. Po = ?.

*February 7, 2016*

**science**

a. h = 0.5g*t^2. h = 20 m., g = 9.8 m/s^2. t = ?. b. d = 10m/s * t. t = Value calculated in part "a".

*February 7, 2016*

**physics**

a. V^2 = Vo^2 + 2g*h = 0. Vo^2 = -2g*h = -(-19.6)*0.18 = 3.53, Vo = 1.88 m/s. b. KE = 0.5M*Vo^2 = 0.5*0.54*10^-6*1.88^2 = 9.54*10^-7 Joules.

*February 7, 2016*

**Physics**

Xo = 2.9 m/s. Tan 43.6 = Y/Xo = Y/2.9. Y = 2.9*Tan 43.6 = 2.76 m/s. V^2 = Vo^2 + 2g*d = 2.76^2. 0 + 19.6d = 7.63, d = 0.389 m. h = 1.14 - 0.389 = 0.751 m. Above the floor.

*February 6, 2016*

**physics**

See previous post: Thu,2-4-16, 11:20 AM.

*February 5, 2016*

**Physics**

Oops! The name is Henry.

*February 4, 2016*

**science**

V^2 = Vo^2 + 2g*h. Vo = 0, g = 9.8 m/s^2, h = 80 m. V = ?.

*February 4, 2016*

**Physics**

Xo = 19.8 m/s. Yo = 16.4 m/s. a. Y = Yo + g*Tr = 0, Tr = -Yo/g = -16.4/-9.8 = 1.67 s. = Rise time. b. h = Yo*Tr + 0.5g*Tr^2. g = -9.8 m/s^2. c. T = Tr+Tf, Tf = Tr = 1.67 = Fall time. T = Tr+Tr = 1.67 + 1.67 = d. T = 2Tr. e. d = Xo*T.

*February 4, 2016*

**physics**

0.5g*t^2 = 25 m. 4.9*t^2 = 25, t^2 = 5.1, t = 2.26 s. Y = Yo + g*t = 0 + 9.8*2.26 = 22.1 m/s. = Ver. component of final velocity. V = 16 + 22.1i = 27.3m/s[54.1o].

*February 4, 2016*

**physics help please**

See previous post: Thu, 2-4-16, 10:47 PM.

*February 4, 2016*

**physics**

See previous post: Wed, 2-3-16, 11:49 AM.

*February 4, 2016*

**Math**

1. 12.5/10.5 = 1.190 = 119%. 119%-100% = 19% Increase. 2. 71.4/80.2 = 0.890 = 89.0% 89%-100% = -11% = 11% Decrease.

*February 4, 2016*

**maths**

X votes. x+300 Votes. Total = x + x+300 = 2x+300. x/(2x+300) = 0.4 x = 0.8x + 120 0.2x = 120. X = 600. Total = 2x+300 = 2*600 + 300 = 1500 votes.

*February 4, 2016*

**physics**

Energy = P*t = 6*0.5 * 5/60 = 0.25 Watt-hours.

*February 4, 2016*

**Physics**

L = V/F, F = V/L. The one with the shortest wavelength(2) has the highest freq. or pitch.

*February 4, 2016*

**physics**

C = pi*2r = 3.14 * 40 = 125.6 cm. A = 360o/125.6cm * 30cm = 86o.

*February 4, 2016*

**Physics**

Vo = 10.1m/s[62.4o]. Yo = 10.1*sin62.4 = 8.95 m/s. Y^2 = Yo^2 + 2g*h. Y = 0, g = -9.8 m/s^2, h = ?.

*February 3, 2016*

**Math**

d = r*t = 40 * 3 = 120 mi. d = 60 * T =120, T = 120/60 = 2 h.

*February 3, 2016*

**Physics**

Unless otherwise stated, all angles are measured CCW from +x-axis. a. F=267[23o] - 377=245.8+104.3i - 377 = -131.2 + 104.3i = 168N[38.5o]N. of W. b. F3 and F should be equal in magnitude and 180o out of phase: Therefore, F3 = 168N[38.5o]S. of E.

*February 3, 2016*

**physic**

Oops! Disregard last line of this post.

*February 3, 2016*

**physic**

Vo = 15m/s[35o]. Yo = 15*sin35 = 8.60 m/s. Y = Yo + g*Tr = 0, Tr = -Yo/g = -8.60/-9.8 = 0.88 s. = Rise time. h1 = Yo*Tr + 0.5g*Tr^2. h1 = 8.60*0.88 - 4.9*0.88^2 = 3.77 m. Above top of bldg. Tr+Tf = 2.7, Tf = 2.7-Tr = 2.7-0.88 = 1.82 s. = Fall time from max ht. to gnd. h2 = 0....

*February 3, 2016*

**physic**

Tr = Rise time, Tf = Fall time. a. Tr + Tf = 2 s, Tf = Tr, Tr+Tr = 2, 2Tr = 2, Tr = 1 s. V = Vo + g*Tr = 0, Vo = -g*Tr = 9.8*1 = 9.8 m/s. b. Yo = 9.8 m/s(Part a), Vo*sin40 = 9.8, Vo = 9.8/sin40 = 15.25 m/s.

*February 3, 2016*

**physics**

a. V = 205mi/h * 1600m/mi * 1h/3600s = 91.1 m/s. V = Vo + a*t. V = 91.1 m/s, Vo = 0, t = 2.70 s. a = ?. b. d = 0.5a*t^2. a = Value cal. in part "a", t = 2.70 s, d = ?.

*January 31, 2016*

**physics**

a. V^2 = Vo^2 + 2g*h V = 0, Vo = 19.0 m/s, g = -9.8 m/s^2, h = ? b. V = Vo + g*t. V = 0, Vo = 19.0 m/s,g = -9.8 m/s^2, t = ?.

*January 31, 2016*

**science**

100%-30% = 70% Below the surface. Db/Dw = 0.7, Db = 0.7Dw = 0.7*0.998 = 0.699 g/cm^3.

*January 31, 2016*

**SCIENCE**

Wo = F*d=M*g * d = 150*9.8 * 2.5 = 3675 J. = Work output or work done. Input = 3675/0.6, but it did not ask for the input.

*January 31, 2016*

**science**

M*V = 1.4, 0.7*V = 1.4, V = ?.

*January 30, 2016*

**math**

100%-8% = 92%. Cost = 0.92 * 968

*January 30, 2016*

**Physics**

See previous post: Tue, 1-26-16, 1:52 PM.

*January 30, 2016*

**Math**

See previous post.

*January 29, 2016*

**Math**

See previous post.

*January 29, 2016*

**Math**

-15x+3 >= -3(4x-7). -15x+3 >= -12x+21. -15x + 12x >= 21-3. -3x >= 18. X <= -6. When multiplying or dividing an inequality by a negative number, the inequality sign should be reversed.

*January 29, 2016*

**science(physics)**

a. Vo = 36000m/3600s. = 10 m/s. a = -(Vo^2)/2d = -(10^2)/80 = -1.25 m/s^2. b. F = M*a = 100 * (-1.25) = -125 N. The negative sign means the force opposes the motion.

*January 28, 2016*

**Physics**

Xo = 21 m/s. Yo = 45 m/s. 1. Y = Yo + g*Tr = 0 at max.ht. Tr = -Yo/g = -45/-9.8 = 4.59 s. = Rise time. Tf = Tr = 4.59 s. = Fall time. Tr+Tf = 4.59 + 4.59 = 9.18 s. = Time in air. 2. R = Xo*(Tr+Tf) = 21m/s * 9.18s = 193 m. 3. A = 45o for max range. Vo = Sqrt(21^1+45^2) = 49.7 m...

*January 28, 2016*

**Physics - Am I correct?**

See previous post: Tue, 1-26-16, 1:52 PM.

*January 28, 2016*

**physic**

KE = 0.5*M*V.

*January 28, 2016*

**Physics**

Tan A = Y/X = 2.77/17.6 = 0.15737 A = 8.94o = Direction.

*January 28, 2016*

**Physics**

Vo = 18.7m/s[20o]. Xo = 18.7*Cos20 = 17.6 m/s. Yo = 18.7*sin20 = 6.40 m/s Y = Yo + g*t = 6.40 - 9.8*0.37 = 2.77 m/s. Tan A = Y/Xo = 2.77/17.6 = 8.94o = Direction.

*January 28, 2016*

**math**

(3x+2)^(1/3) = -2. Cube both sides: 3x+2 = -8. 3x = -10. X = -10/3.

*January 28, 2016*

**Physics**

1. V = Vo + g*t, g = -9.8 m/s^2. 2. a = g = -9.8 m/s^2. 3. V = Vo + g*Tr, V = 0, Vo = 70 m/s, g = -9.8 m/s^2, Tr = Rise time, Solve for Tr. 4. Tf = Fall time, T = Tr+Tf, Tf = Tr, T = Tr+Tr = 2Tr = Time required to reach gnd. 5. V^2 = Vo^2 + 2g*h = 0, h = -(Vo^2)/2g, g = -9.8 m...

*January 28, 2016*

**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*