Friday

September 30, 2016
Total # Posts: 12,073

**maths**

X boys. 3x/7 girls. x + 3x/7 = 30. 7x + 3x = 210. 10x = 210. X = 21.

*September 27, 2015*

**science**

h = 0.5g*t1^2 = 500 m. 5t1^2 = 500. t1^2 = 100. t1 = 10 s. = Fall time. h = Vs*t2 = 500. 340*t2 = 500. t2 = 1.47 s. To travel 500 m. t1+t2 = 10 + 1.47 = 11.47 s. To hear the sound of the stone.

*September 27, 2015*

**Phy**

Wb = M*g = 3.09 * 9.8 = 30.3 N. Fn = 30.3 - 13.7*sin23 = 24.9 N. = Normal. a. a = 13.7*Cos23/3.09 = 4.08 m/s^2.

*September 26, 2015*

**Physics**

F = 10.3i + 19.5 - 15.2i = 19.5 - 4.9i. X = 19.5, Y = -4.9. F = Sqrt(X^2 + Y^2)=Sqrt(19.5^2+4.9^2) = 20.1 N. a = F/M = 20.1/4.06 = 4.95 m/s^2. Note: The direction(angle) is not required.

*September 26, 2015*

**physics**

All angles are CCW from the +x-axis. D = 3.6m[90o] + 2.8[45o] + 2.2[211o]. X = 3.6*Cos90 + 2.8*Cos45 + 2.2*cos211 = 0 + 1.98 - 1.89 = 0.09 m. Y = 3.6*sin90 + 2.8*sin45 - 2.2*sin211 = 3.6 + 1.98 - 1.13 = 4.45 m. D = Sqrt(X^2 + Y^2).

*September 25, 2015*

**math**

See previous post: Fri, 9-25-15, 11:35 AM.

*September 25, 2015*

**math**

20-year fixed: P = Po*r*t/(-(1+r)^-t). Po = 35000*0.95 = $33,250. r = (7.5%/12)/100% = 0.00625 = Monthly %rate expressed as a decimal. t = 20yrs. * 12mo./yr. = 240 Months. P1 = 33,250*0.00625/(1-1.00625^-240) = $64,286.34. I = P1-Po=64,286.34-33,250=$31,036.34. 30-year fixed...

*September 25, 2015*

**physics**

V = Vo + g*Tr = 0. Tr = -Vo/g = -7.5/-9.81 = 0.77 s. = Rise time. Tf = Tr = 0.77 s. = Fall time. V = Vo + g*Tf. Vo = 0. g = 9.81. V = ?.

*September 25, 2015*

**physics**

V^2 = Vo^2 + 2g*h. Vo = 0. g = 3.7. h = 323 m. V = ?.

*September 25, 2015*

**physics**

See previous post: Fri, 9-25-15, 7:13 AM

*September 25, 2015*

**Kabe college**

Fr = Sqrt(F^2 + F^2) = Sqrt(2F^2) = 1.414F.

*September 25, 2015*

**physics**

V = Vo + g*Tr = 0. Tr = -Vo/g = -150/-10 = 15 s. = Rise time. Tf = Tr = 15 s. Tr+Tf = 15 + 15 = 30s. = Time in flight. V = Vo + g*Tf = 0 + 10*15 = 150 m/s. = Final velocity. h = Vo*Tr + 0.5g*Tr^2. Vo = 150 m/s. Tr = 15 s. g = -10 m/s^2. h = ?.

*September 25, 2015*

**physics**

Vo = 80000m/3600s = 22.2 m/s. V = 92000m/3600s = 25.6 m/s. V^2 = Vo^2 + 2a*d. d = (V^2-Vo^2)/2a.

*September 25, 2015*

**Physics**

Vo = 27m/s[42o]. Xo = 27*Cos42 = 20.1 m/s. Yo = 27*sin42 = 18.1 m/s. a. Y = 0, V = Xo = 20.1 m/s. b. Y^2 = Yo^2 + 2g*h = 0. h = -Yo^2/2g = -(18.1^2)/-19.6 = 16.7 m, max. Y^2 = Yo^2 + 2g*h/2. = 0 + 19.6*8.35 = 163.66. Y = 12.8 m/s. V = Sqrt(Xo^2 + Y^2). c. (Xo+Y) - Xo = (20.1+...

*September 25, 2015*

**Physics - URGENT**

46N.[52o] + 29[0o] + 34.5[270o]+F4 = 0. 46*Cos52 + i46*sin52 + 29 -34.5i +F4=0 28.32 + 36.25i + 29 - 34.5i + F4 = 0. 57.32 + 1.75i + F4 = 0. F4 = -57.32 - 1.75i. X = -57.32 N., Y = -1.75 N. F4 = sqrt(X^2 + Y^2).

*September 25, 2015*

**Physics**

Incomplete.

*September 25, 2015*

**Physics**

d1 = 88 m. V^2 = Vo^2 + 2a*d1. a = (V^2-Vo^2)/2d1=(7^2-15^2)/176 = -1.0 m/s^2. d2 = (V^2-Vo^2)/2a=(0-15^2)/-1.0 = 225 m d = d2-d1 = 225 - 88 = 137 m.

*September 25, 2015*

**physics**

ge = 6*gm.

*September 24, 2015*

**Physics**

See previous post: Thu, 9-24-15, 10:35 PM.

*September 24, 2015*

**Physics**

Ws = M*g = 49 * 9.8 = 480 N. = Wt. of sofa. Fp = 480*sin30 = 240 N. = Force parallel to ramp. Fn = Normal = 480*Cos30 = 416 N. = Force perpendicular to incline. Fk = u*Fn = 0.320 * 416 = 133 N. = Force of kinetic friction. T-Fp-Fk = M*a. T-240-133 = 49*0.80, T-373 = 39. T = ...

*September 24, 2015*

**physics1**

See previous post: Thu, 9-24-15, 7:24 PM

*September 24, 2015*

**physics**

See previous post: Thu, 9-24-15, 7:24 PM

*September 24, 2015*

**Physic**

See previous post: Thu, 9-24-15, 7:24 PM

*September 24, 2015*

**Physic**

R = 9[30.4o] + 12[102.3o] + 18[180o] + 16[293.8o]. X = 9*Cos30.4+12*Cos102.3+18*Cos180+ 16*Cos293.8 = Y = 9*sin30.4+12*sin102.3+18*sin180+ 16*sin293.8 = R = sqrt(X^2 + Y^2).

*September 24, 2015*

**Physics**

2. a, and b. 3. b.

*September 24, 2015*

**Physics**

1. Area = pi*r^2. 2. You cannot add time and distance, but you can divide: V = d/T or distance per unit of time.

*September 24, 2015*

**Physics**

V^2 = Vo^2 + 2g*h. Vo = 0. g = 9.8 m/s^2. h = 12 m. V = ?.

*September 24, 2015*

**math fraction**

1/5 * 1/2 = 1/10. 3/4 * 1/2 = 3/8. Bal.=1/2 - (1/10+3/8)=1/2-(4/40+15/40) = 1/2 - 19/40 = 20/40 - 19/40 = 1/40.

*September 23, 2015*

**physics**

d = Vo*t = 21m/s * 0.245s = V^2 = Vo^2 + 2a*d. V = 0. Vo = 21 m/s. a = -5.29 m/s. d = ?.

*September 23, 2015*

**physics**

D = 2000[145o] + 500[270o]. X = 2000*Cos145 + 500*Cos270 = -1638+0 = -1638 km. Y = 2000*sin145 + 500*sin270 = 1147-500 = 647 km. Q2. Tan A = Y/X = 647/-1638 = -0.39499. A = -21.6o N. of W. = 158.4o CCW. = Direction. D = X/Cos A = -1638/Cos158.4 = 1762 km.

*September 21, 2015*

**physics**

0.5g*t^2 = 30.2-17.4 = 12.8 m. Above gnd 4.9*t^2 = 12.8. t^2 = 2.61 s.

*September 21, 2015*

**physics**

V = Vo + g*t = 0 @ max ht. t = -Vo/g = -9/-9.8 = 0.92 s.

*September 21, 2015*

**Physics**

F = 6.90[54o] + 5[90o] X = 6.9*Cos54 + 5*Cos90 = 4.1 Units. Y = 6.9*sin54 + 5*sin90 = 10.6 Units. Q1. F = sqrt(X^2 + Y^2) = 11.4 Units. Tan A = Y/X = 10.6/4.1 = 2.58537. A = 68.9o CCW = Direction. OR: Y = F*sin A = 10.6. sin A = 10.6/F = 10.6/11.4 = 0.92982. A = 68.4o CCW.

*September 20, 2015*

**physics**

X = 225*Cos12 = 220.1 N. Y = 225*sin12 = 46.8 N.

*September 20, 2015*

**Physics**

Wb = M*g = 17.8 * 9.8 = 174.4 N. Fn = Mg-Fap*sin31.3 = 174.4-72.8*sin31.3 = 136.6 N. = Normal force. Fk = u*Fn = 0.239*136.6 = 32.7 N. Work = (Fap*Cos31.3-Fk) * d = (72.8-32.7) * 64.4 =

*September 20, 2015*

**Physics**

M*g = 800 N. = Normal(Fn). Fap-Fk = M*a. 60-u*800 = M*0 = 0. u*800 = 60. u = 0.075.

*September 20, 2015*

**Physics**

V = Vo + a*t. V = 13.5 m/s. Vo = 17.3 m/s. a = -2.8 m/s^2. t = ?.

*September 20, 2015*

**Physics-HELP**

Dx = Xo*t = 7.5 m. 8.8 * t = 7.5. t = 0.852 s. h = 0.5g*t^2. g = 9.8 m/s^2. t = 0.852 s. h = ?.

*September 20, 2015*

**math foe managers**

1st number = X. 2nd number = Y. Eq1: 5x + 3y = 47. Eq2: 10x - 4y = 54. Solve the Eqs using the Elimination Method: Multiply Eq1 by -2 and add the Eqs.

*September 20, 2015*

**physics**

Dc = Dt + 150 0.5a2*t^2 = 0.5a1*t^2. + 150. a1 = 1.5 m/s^2. a2 = 2 m/s^2. t = ?. Dc = 0.5a2*t^2 =

*September 20, 2015*

**Physics**

a. h = 0.5g*t^2. b. Dx = Xo*t = 10m/s * 5s. = 50 m.

*September 20, 2015*

**Finance**

Incomplete.

*September 20, 2015*

**Physics**

V = Vo + a*t. V = 10 m/s. Vo = 98 m/s. a = (V^2-Vo^2)/2d. It will be negative. t = ?.

*September 20, 2015*

**science**

V = 3*10^8 m/s = Speed of light.

*September 20, 2015*

**Math**

L = 738/6h * 9h =

*September 20, 2015*

**Math**

5000/3 * n = 250,000. Multiply both sides by 3: 5000n = 750,000. n = 150 Months. = 12.5 years.

*September 20, 2015*

**Math**

L = 738/6h * 9h =

*September 20, 2015*

**phyics**

a = (V-Vo)/t m/s^2. V = 22 m/s. Vo = 0. t = 11 s.

*September 19, 2015*

**physics**

E = V1+V2+V3 = 15. V1 = 3 Volts. V2 = 10 Volts. V3 = ?.

*September 19, 2015*

**physics**

P = 0.5M*V^2/6 = 0.5*1100*27^2/6 = 66,825 J/s = 66,825 W. hp = 66825/746 = 89.6.

*September 19, 2015*

**physics**

a = (V-Vo)/t = (27-0)/6 = 4.5 m/s^2. d = 0.5a*t^2 = 0.5*4.5*6^2 = 81 m. Power = F*d/t = Mg*d/t = 1100*9.8*81/6 = 145,530 J/s. = 145,530 Watts. hp = 145,530/746 = 195.1.

*September 19, 2015*

**Physics**

Fr = 20N[30oCCW] + 60N[180oCCW] = Resultant force. X = 20*Cos30 + 60*Cos180 = 17.3 - 60 = -42.7 N. Y = 20*sin30 + 60*sin180 = 10 + 0 = 10 N. Tan A = Y/X = 10/-42.7 = -0.23419. A = -13.2o = 76.8o W. of N. = Direction. Fr = sqrt(X^2 + Y^2) = Note: This not a graphical method.

*September 19, 2015*

**Physics**

V^2 = Vo^2 + 2a*d. V = 0. a = -10.3 m/s^2. d = 65 m. Vo = ?.

*September 19, 2015*

**Physics**

a. Q1 = C*V = 11 * 55 = Micro Coulombs. Q2 = 50 * 55 = Micro Coulombs. b. The capacitors will discharge: Q = C*V = 61 * 0 = 0. c. 0 volts.

*September 19, 2015*

**Physics**

V = Vo + g*t. Vo = 5 m/s. g = 9.8 m/s^2. t = 1.8 s. V = ?.

*September 18, 2015*

**Logarithm help**

(1+x)*Log5 = (1-x)*Log2. Divide both sides by Log5: 1+x = (1-x) * 0.431. 1+x = 0.431-0.431x. 1.431x = -0.569. X = -0.398.

*September 18, 2015*

**Physics**

Incomplete.

*September 18, 2015*

**Maths**

See previous post: Fri, 9-18-15, 2:31 AM

*September 18, 2015*

**Physics**

Faster runner: d = V*t = 5.0 km. 14.7*t = 5. t = 0.340 h. Slower runner: 11.8*t = 5.0 t = 0.424 h. T = 0.424 - 0.340 = 0.0837 h = 5.02 min. = Wait time.

*September 17, 2015*

**physics**

D = 58 + 16[90o] + 15[45o]. X = 58 + 16*Cos90 + 15*Cos45 = 58 + 0 + 10.6 = 68.4 km. Y = 0 + 16*sin90 + 15*sin45 = 0 + 16 10.6 = 26.6 km. D = sqrt(X^2 + Y^2) km. Note: Northeast = 45o N. of E.

*September 17, 2015*

**Physics**

You should change the meters to km or the km to meters: V = 220,000 m/h. d = 500 m. OR: V = 220km/h. d = 0.50km.

*September 17, 2015*

**physics**

Correction: Replace 200 with 220.

*September 16, 2015*

**physics**

Dc = 220 + Dt. 30*t = 200 + 22*t. t = ?.

*September 16, 2015*

**Physics**

a. V = Vo + g*t. V = 0 @ max h. Vo = 7.8 m/s. g = -9.8 m/s^2. t = ? b. h = 1.5 + Vo*t + 0.5g*t^2. Vo = 7.8 m/s. t = Value calculated in part a. g = -9.8 m/s^2. h = ? c. V^2 = Vo^2 + 2g*d. Vo = 7.8 m/s. g = -9.8 m/s^2. d = 2.2-1.5 = 0.7 m. V = ?. d. V^2 = Vo^2 + 2g*h. Vo = 0 @ ...

*September 16, 2015*

**physics**

V = a*t = 11.1 m/s. a*2.54 = 11.1. a = 4.37 m/s^2. d1 = 0.5a*t^2 = 0.5*4.37*2.54^2 = 14.1 m d2 = V*t = 100-14.1. 11.1*t = 85.9. t = 7.74 s. 2.54 + 7.74 = 10.3 s. = Total time.

*September 16, 2015*

**physics**

D = -18 + 16i + 49 = 31 + 16i = sqrt(X^2 + Y^2) = sqrt(31^2 + 16^2) =

*September 16, 2015*

**maths**

(x-2)^2 + 3x^2 = (x+3)^2. x^2-4x+4 + 3x^2 = x^2+6x+9. 3x^2-10x = 5. 3x^2 - 10x -5 = 0. Use Quadratic Formula. X = 3.77, and -0.442.

*September 16, 2015*

**Physics**

a. V=Vo + a*t=10.3 + 0.37*7.01=12.9 m/s.

*September 15, 2015*

**Trigonometry**

X1 = Distance from closest point to bottom of mountain. X1+13 = Distance from farthest point to bottom of mountain. Tan9.5 = h/X1, h = X1*Tan9.5. Tan4.5 = h/(X1+13), (X1+13)*Tan4.5. h = X1*Tan9.5 = (X1+13)*Tan4.5 X1 = 0.507(X1+13) = 0.507X1+6.59. X1-0.501X1 = 6.59. 0.5X1 = 6....

*September 15, 2015*

**Math**

1. 28x - 6(3x-5) = 60. 28x - 18x + 30 = 60. 10x = 30. X = 3. 2. 3(x-2)-8x < 44. 3x-6-8x < 44. -5x < 50. X > -10. Note: When I divided by (-5), I reversed the inequality sign.

*September 15, 2015*

**physics**

d = 3*10^8m/s * 8.3min*60s/min = 1.494*10^11 m.

*September 15, 2015*

**Physics**

A. d = V*t = 1700 m. 6.6*t = 1700. t = 258 s. B. T = 258 + 1700m/2s. C. T/60 = ? D. d = 2 * 1.7km = 3.4 km. E. D = 0.(The end = The beginning). F.

*September 15, 2015*

**Physics**

d = 3cm/yr * T = 5.0*10^7 cm. T = 1.67*10^7 years.

*September 14, 2015*

**Physics**

M*g = 10 * 9.8 = 98 N. = Wt. of object = Normal(Fn). Fs = u*Fn = 0.7 * 98 = 6.86 N. = Force of static friction. F-Fs = M*a. F-6.86 = 10*0 = 0. F = 6.86 N. Angle = 0o(parallel to the surface).

*September 14, 2015*

**College Physics**

Range = Vo^2*sin(2A)/g = 300 m. Vo = 700 m/s. g = 9.8 m/s^2. A = ?

*September 14, 2015*

**PHYISCS**

V^2 = Vo^2 + 2g*h. V = 0. g = -9.8 m/s^2. h = 4.6 m., max. Vo = ?.

*September 14, 2015*

**precalc**

Cot 2pi/5 = 1/Tan2pi/5 = 1/Tan72o = 0.325.

*September 14, 2015*

**Physics**

V1 = a*t = 4 * 6 = 24 m/s. d1 = 0.5a*t^2 = 0.5*4*6^2 = 72 m. d2 = V*t = 24 * 8 = 192 m. V = Vo + a*t = 0. a = -Vo/t = -24/10 = -2.4 m/s^2. V^2 = Vo^2 + 2a*d = 0. d3 = -(Vo^2)/2a = -(24^2)/-4.8 = 120 m. d = d1+d2+d3.

*September 14, 2015*

**Inverse Functions**

X = 1450 Ft. Y = 850 Ft. Tan A = Y/X.

*September 14, 2015*

**physique**

X = Vp = 320 km/h. Y = Vw = 65km/h. Vr = sqrt(X^2 + Y^2) = Resultant velocity.

*September 14, 2015*

**Physics**

V^2 = Vo^2 + 2g*h. V = 0. Vo = 8.2 m/s. g = -9.8 m/s^2. h = ? V = Vo + g*Tr. V = 8.2 m/s. Vo = 0. g = -9.8 m/s^2. Tr = ? = Rise time. Tf = Tr = Fall time. Tr+Tf = Time to return to starting point. V^2 = Vo^2 + 2g*h. Vo = 8.2 m/s. g = +9.8 m/s^2. h = 50 m. V = ?.

*September 14, 2015*

**Physics**

X = Vc = 3.5 m/s. Y = Vb = 9.5 m/s. Tan A = Y/X = 9.5/3.5 = 2.71429. A = 69.8o Tan 69.8 = 106m/d. d = 106/Tan69.8 = 39.1 m. Downstream.

*September 14, 2015*

**Math**

Vr=50[315oCCW] + 150[30oCCW] = Resultant velocity. X = 50*Cos315 + 150*Cos30 = 165.3 km. Y = 50*sin3i5 + 150*sin30 = 39.64 km. Tan A = Y/X = 39.64/165.3 = 0.23981. A = 13.5o. Vr=X/Cos A=165.3/Cos13.5 = 170km[13.5o] CCW. = 170km[N76.5oE].

*September 14, 2015*

**phsyics**

Incomplete.

*September 13, 2015*

**math**

X = ? Y = 10+2 = 12 m. L = 15 m. Sin A = Y/L = 12/15 = 0.80, A = 53.1o X = L*Cos A = 15*Cos53.1 = 9 m.

*September 13, 2015*

**Physics 111**

We need to know the width of the river.

*September 13, 2015*

**Physics**

V1 = a*t = 15 * 2.8 = 42 m/s. d1 = 0.5a*t^2 = 0.5*15*2.8^2 = 58.8 m. V^2 = V1^2 + 2a*d = 0. d = -V1^2/2a = -(42^2)/-7 = 252 m. Final position = 7800 + 252 = 8052 m. mark.

*September 13, 2015*

**Physics**

a. d1 = V*t=2m/s. * 1s.=2 m. Head start. d2 = 2 + d1. 0.5a*t^2 = 2 + V1*t. 0.5*0.2*t^2 = 2 + 2*t. 0.1t^2 -2t - 2 = 0. Use Quadratic Formula. t = 21 s. b. d = 2 + 2*21 = 44 m.

*September 13, 2015*

**Physics**

V^2 = Vo^2 + 2g*h. V = 0 @ max h. Vo = 19.8 m/s. g = -9.8 m/s^2. h = ?

*September 13, 2015*

**Physics**

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

*September 13, 2015*

**physics**

See previous post: Sun, 9-13-15, 4:17 PM.

*September 13, 2015*

**Physics**

d = 0.5a*t^2 = 0.5*17*11^2 =

*September 13, 2015*

**physics**

d = 0.5g*t^2 = 0.55 m. 4.9t^2 = 0.55. t^2 = =.112. t = 0.335 s. = Fall time. Dx = Xo * t = 12 m. Xo * 0.335 = 12. Xo = 35.8 m/s.

*September 13, 2015*

**Physics**

V = Vo = 8m/s.

*September 13, 2015*

**Sicience**

Density = 20g/315.4mL = g/mL.

*September 13, 2015*

**physics**

V = Vo + g*Tr. V = 0 Vo = 8.7 m/s. g = -9.8 m/s^2. Tr = ? = Rise time. Tf = Tr = Fall time. Tr+Tf = Time in air.

*September 13, 2015*

**Math (Trigonometry)**

X1 m.= Naeem's distance from base of tower. X2 = distance between Zola and Naeem. X1+X2 = Zola's distance from base of tower. Tan 50 = h/X1 = 180/X1. X1 = 180/Tan50 = 151 m. Tan32 = 180/(X1+X2) = 180/(151+X2). (151+X2) = 180/Tan32 = 288. X2 = 137 m.

*September 13, 2015*

**Physics**

6. V = 2.2 + 5.225 = 7.425 m/s. 7. a. 4 sig. fig. b. A = 47 * 31.25 = 1469 cm^2. 8. a. P = 2L + 2W. b. A = L*W.

*September 13, 2015*

**Physics**

Vo = 30000m/3600s. = 8.33 m/s. V^2 = Vo^2 + 2a*d = 8.33^2 + 2*3*100 = 69.44 + 600 = 669.44. V = Sqrt(669.44) = 25.87 m/s.

*September 13, 2015*

**Physics**

kilo means 1000 units. 1450 m./1000 = 1.450 km.

*September 13, 2015*