Monday

September 26, 2016
Total # Posts: 12,051

**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*

**math**

See previous post: Sun, 9-13-15, 3:47 AM.

*September 13, 2015*

**Math**

X = Vw = -85 km/h. Y = Vp = 230 km/h. a. Vr = sqrt(X^2 + Y^2) = b. Tan A = Y/X = 230/-85 = -2.70588. A =-69.7o=69.7o N. of W. = 20.3o W. of N. = Bearing.

*September 13, 2015*

**algeb**

3 years ago: Paul was X yrs. old. Vin was 3x yrs. old. At the present: Paul is x+3 yrs. old. Vin is 3x+3 yrs. old. x+3 + 3x+3 = 18. 4x = 12. X = 3. Paul = x+3 = 3+3 = 6 yrs. old. Vin = 3x+3 = 3*3 + 3 = 12 yrs. old. 3yrs. from now: Paul = 6+3 = 9 yrs. old. Vin = 12+3 = 15 yrs. ...

*September 13, 2015*

**Algebra**

d = (Vb-Vc)*T = 6km. (Vb-4)T = 6. Eq1: Vb*T - 4T = 6. (Vb+Vc)*T = 10 km. (Vb+4)*T = 10. Eq2: Vb*T + 4T = 10. Subtract the Eqs: Vb*T - 4T = 6. Vb*T + 4T = 10. -8T = -4. T = 0.5h. In Eq1, replace T with 0.5h: Vb*0.5 - 4*0.5 = 6. 0.5Vb = 8. Vb = 16 km/h.

*September 12, 2015*

**Physics**

Sin A = 0.05, A = 2.87o. Fp = Mg*sin2.87 = 1963 N. = Force parallel to the incline. V^2 = Vo^2 + 2a*d = 144. a = 144/2d = 144/400 = 0.36 m/s^2. F-1963 = 4000*0.36 = 1440. F = 3403 N.

*September 12, 2015*

**Algebra**

Y = 4x^2 + 3x - 1. Factor it: A*C = 4*(-1) = -4. 4x^2 + (4x-x) - 1. 4x^2+4x - (x+1). 4x(x+1) - (x+1). Y = (x+1)(4x-1). All real values of x will give a real output. Therefore, the domain is all real values of x. Interval notation: -infinity < X < +infinity. So x must be ...

*September 12, 2015*

**Algebra**

X = Ferns' score. 2x-28 = D. + E. score. x + 2x-28 = 272. 3x = 300. X = 100. 2x-28 = 2*100 - 28 = 172 = D. + E. Y = D. score. Y+8 = E. score. Y + Y+8 = 172. 2y = 164. Y = 82. Y+8 = 82 + 8 = 90.

*September 12, 2015*

**algebra**

P1 = Po(1+r)^n. Po = $25,000. r = (5.35%/4)/100% = 0.01338 = Quarterly % rate expressed as a decimal. n = 4comp./yr. * 5yrs. = 20 Compounding periods. P2 = Po(1+r)^n. r = 2.6%/100% = 0.026 = Annual % rate. n = 1comp./yr. * 5yrs. = 5 Compounding periods. P1+P2 = Total Amt.

*September 12, 2015*

**math**

2/5-3/7 - 1/6*3/2 + 1/14*2/5 = 14/35-15/35 - 3/12 + 2/70 = -1/35 - 1/4 + 1/35 = -1/4.

*September 12, 2015*

**Physics**

T = 150/60 = 2.5 h. d = V*T = 24 * 2.5 = 60 mi. Mile Marker = 132 + 60.

*September 12, 2015*

**physics**

Assume the car is coasting up the incline. At the bottom of the incline, the KE is at its' max value; and PE is zero. KE + PE = Constant. At bottom of incline, assume KE = 20 J., PE = 0. KE + PE = 20 + 0 = 20 J. Half-way up the incline, KE = 10 J. and PE = 20-10 = 10 J. KE...

*September 11, 2015*

**Physics-Trajectory**

A. Speed = 0. B. X = 12*5^3 - 2*5^2 = Y = 12*5^2 - 2*5 = Speed = sqrt(X^2 + Y^2) = C. D. Tan A = Y/X. A = ?

*September 11, 2015*

**Physics**

I need to know the direction(angle) of the forces.

*September 11, 2015*

**Physics**

Tan A = Y/X = -4.0/3.90 = -1.02564. A = -45.7o = 45.7o CW from +x-axis. = 314.3o CCW from +x-axis.

*September 11, 2015*

**Physics**

A. X = 8*2 = 16 cm/s. Y = 30 cm/s. Tan A = Y/X = 30/16 = 1.875. A = 61.9o B. X = 8*3 = 24 cm/s. Y = 30 cm/s. Dx = 24cm/s * 3s = 72 cm. Dy = 30cm/s * 3s = 90 cm. D = sqrt(Dx^2 + Dy^2) =

*September 11, 2015*

**physics**

When they meet: Da + Db = 350 km. 60*T+0.5*a*T^2 + 45*T = 350. a = 5 m/s^2. T = ?

*September 11, 2015*

**physics**

a. 0.03L = 1 oz. L = 33.4 oz. M = 0.454kg/16oz * 33.4oz = 0.948 kg.

*September 11, 2015*

**physics**

V = Vo + g*Tr = 0 @ max ht. Tr = -Vo/g = -17.5/-9.8 = 1.79 s. = Rise time. Tf = Tr = 1.79 s. = Fall time. Tr + Tf = 1.79 + 1.79 = 3.58 s = Time in flight. d = Vc*(Tr+Tf) = 17.5 * 3.58 = 62.7 m.

*September 11, 2015*

**physics**

X = Vc = 1.19 m/s. Y = Vs = 1.18 m/s Vr = sqrt(Vc^2 + Vs^2) = 1.68 m/s = Resultant velocity. Tan A = 1.18/1.19 = 0.99160 A = 44.8o a. d1=2.16/sin44.8 = 3.07 km. = 3070 m. Vr*T = 3070. 1.68*T = 3070. T = 1827 s. = 30.5 Min. b. d2 = 2.16/Tan44.8 = 2.175km = 2175 m. = Distance ...

*September 11, 2015*

**Math**

A = 2pi/3 = 360/3 = 120o. 120-360 = -240o.

*September 11, 2015*

**Physics**

Since the h is the same, the Fall time is the same: t2 = t1 = 2.8 s. d = 2 * 100 = 200 m.

*September 11, 2015*

**math Help**

1. (2/3)/1/4 = 2/3 * 4/1 = 8/3 = 2 2/3. 2. 2/3*5/2 = 10/6 = 1 2/3. 3. 9/4 * 5/2 = 45/8 = 5 5/8 Cups. 4. 1/4 * 1/4 = 1/16. 5. 1/16 * 1/4 = 1/64

*September 11, 2015*