Sunday

January 22, 2017
Total # Posts: 13,047

**Physics**

a. d1 + d2 = 30 m. 0.5a1*t^2 + 0.5a2*t^2 = 30. 0.5*0.49*t^2 + 0.5*0.43*t^2 = 30. t = ?. b. d1 = 0.5a1*t^2.

*September 29, 2015*

**Physics**

a = (Vf-Vo)/t = (6.20-0)/3.56. d = 0.5a*t^2.

*September 29, 2015*

**physics**

Vc + Vb = 6 + 10i = 11.7km/h[59o] CCW. = 31o E. of N. Boat should sail 31o W. of N.

*September 29, 2015*

**Physics Projectile Motion**

See previous post: Mon, 9-28-15, 10:47 PM.

*September 29, 2015*

**Advanced functions**

No. Going twice as far does not change the braking distance if the initial velocity(Vo) remains constant over that distance.

*September 29, 2015*

**Physics Kinematics.**

Xo = 21 m/s. Yo = 16 m/s. a. V = Vo = Sqrt(Xo^2 + Yo^2). b. Y = Yo + g*Tr = 0. 16 - 9.8*Tr = 0. 9.8Tr = 16. Tr = 1.63 s. = Rise time. Tf = Tr = 1.63 s. Tr+Tf = 1.63 + 1.63 = 3.26 s. = Time in air. c. h = 0.5g*Tf^2 = 4.9*1.63^2 = 13 m.

*September 28, 2015*

**Physics 2D Kinematics**

Incomplete.

*September 28, 2015*

**Physics**

Tb + Ts = 2.5 s. Ts = 2.5-Tb. d = Vs*(2.5-Tb) = 16.5 m. 340*(2.5-Tb) = 16.5. 850-340Tb = 16.5. 340Tb = 833.5. Tb = 2.45 s. = Time of the ball. d = Vb*Tb = 16.5. Vb*2.45 = 16.5. Vb = 6.73 m/s.

*September 28, 2015*

**Physics**

Vf = Vo + a*t. Vo = 8.1 m/s. a = 2.8 m/s^2. t = 5.3 s. Vf = ?

*September 28, 2015*

**math**

10^5cal./s * 10s. = 10*10^5 cal. = 1 Million calculations.

*September 28, 2015*

**Physics**

See previous post: Mon. 9-28-15, 3:51 PM.

*September 28, 2015*

**Physics**

X = -4 km. Y = -3.0 km. Q3. Tan A = Y/X = -3/-4 = 0.750 A = 36.9o S of W. = 216.9o CCW. = Direction. Disp. = X/Cos216.9 = -4/Cos216.9=5.0 km.

*September 28, 2015*

**Physics**

Disp. = 48.1*sin15.5 =

*September 28, 2015*

**2nd Law Physics**

A = (180-107)/2 = 36.5o Above the hor. F = 2.31/2 = 1.16 N., each half. sin36.5 = F/T = 1.16/T. T = 1.16/sin36.5 = 1.94 N., each half.

*September 28, 2015*

**physics**

a. distance = 12 + 19 + 12 = 43 km. b. Disp. = 12i + 19 - 12i = 19 km, East.

*September 28, 2015*

**math**

5. P = Po(1+r)^n. Sem1-annually: Po = $7,000. r = (5%/2)/100% = 0.025 = Semi-annual % rate expressed as a decimal. n = 2Comp./yr. * 5yrs. = 10 Compounding periods. P = 7000 * (1.025)^10 = $8960.59. Quarterly: r = (5%/4)/100% = 0.0125 = Quarterly % rate expressed as a decimal. ...

*September 28, 2015*

**math**

d = (70/55)^2 * 79 = 128 Ft.

*September 28, 2015*

**Math**

True or False. 4. -11^2 = -11 * -11 = 121. Simplify. 4.24d^18. 7. Not sure. 8. Not sure.

*September 28, 2015*

**math**

a contractor's crew can frame 3 houses in a week. how long will it take them to frame 54 houses if they frame the same number each week?

*September 27, 2015*

**Physics**

Vo = 12.5m/s[53.1o]. Xo = 12.5*Cos53.1 = 7.51 m/s. Yo = 12.5*sin53.1 = 10.0 m/s. A. h = ho + -(Yo^2)/2g=75 + 10^2/19.6 = 80.1 m. Above gnd. Y = Yo + g*Tr = 0. Tr = -Yo/g = -10/-9.8 = 1.02 s. = Rise time. 0.5q*Tf^2 = 80.1 m. 4.9Tf^2 = 80.1. Tf^2 = 16.34. Tf = 4.04 s. = Fall ...

*September 27, 2015*

**physics**

10 + 5[60o] + F = 0. 10 + 5*Cos60 + i5*sin60 + F = 0. 10 + 2.5 + 4.33i + F = 0. 12.5 + 4.33i + F = 0. F = -12.5-4.33i = 13.2N[W19.1oS]

*September 27, 2015*

**physics**

Disp. = 30i + 40 = 50m[36.9o]. dist. = 30 + 40 = 70 m.

*September 27, 2015*

**physics**

D = -9 + 17i + 46 = 37 + 17i. X = 37yds, Y = 17 yds. D = Sqrt(X^2 + Y^2)

*September 27, 2015*

**Science**

W = F*d = M*g * d.

*September 27, 2015*

**math**

An excellent explanation, Allyson!

*September 27, 2015*

**physics**

F = 10N.[0o] + 20[60o] = 10 + 20*Cos60 + i20*sin60 = 10 + 10 + 17.3i = 20 + 17.3i = 26.5N.[40.9o].

*September 27, 2015*

**Physics**

V = a*t = 15 * 6 = 90 Ft/s.

*September 27, 2015*

**math**

Jose's age = X yrs. Valerie's age = Y yrs. Eq1: X + Y = 78. 9 yrs. ago: Jose's age: x-9 yrs. Valerie's age: y-9 yrs. x-9 = 3(y-9). x-9 = 3y-27. Eq2: x - 3y = -18. Subtract Eq2 from Eq1: Difference: 4y = 96. Y = 24 = Valerie's current age. X + 24 = 78. X = ...

*September 27, 2015*

**math**

Esmeralda = X yrs. old. Gregory = x+2 yrs. old. In 5 years: Esmeralda = x+5 yrs. old. Gregory = x+2 + 5 = x+7 yrs. old. x+5 + x+7 = 42. 2x + 12 = 42. X = 15 = Esmeraldas' current age.

*September 27, 2015*

**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**

a,b. Vb = 6.6m/s[119o] + 4.1 = -3.2 + 5.77i + 4.1 = 0.9 + 5.77i = 5.84m/s[81o] N. of E. = 9o E. of N. c. 130m * 1s/5.77m = 22.53 s.

*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*