Saturday

October 22, 2016
Total # Posts: 12,185

**science**

Efficiency = Output/Input. High friction lowers the output and causes mechanical efficiency to be lowered.

*October 20, 2016*

**physics**

Vo = 80m/s[30o]. Xo = 80*Cos30 = 69.3 m/s. Yo = 80*sin30 = 40 m/s. a. Y = Yo + g*Tr. 0 = 40 - 9.8Tr, Tr = 4.08 s. = Rise time. h = Yo*Tr + 0.5g*Tr^2. h = 40*4.08 -4.9*4.08^2 = 81.6 m. b. Tf = Tr = 4.08 m/s. = Fall time. Tr+Tf = 4.08 + 4.08 = 8.16 s. = Time in air. c. Range = ...

*October 20, 2016*

**Math**

Sign: W = 22/36 * 52 = 32. Ab/As = (36*52)/(22*32) = 2.68. Or Ab/As = (36/22)^2 = 2.68.

*October 20, 2016*

**Physics**

See previous post: Tue, 10-18-16, 8:27 AM.

*October 20, 2016*

**Physics**

M*g = 12*9.8 = 117.6 N. = Wt. of the object. Fp = 117.6*sin56 = 97.5 N. = Force parallel to the slope. a. Work = Fp*d = 97.5 * 34 = 3315 J.

*October 20, 2016*

**Physics**

1. M1*V1 + M2*V2 = M1*V + M2*V. 600*30 + 900*0 = 600V * 900V, 18000 = 1500V, V = 12 m/s. 2. V = Vo + a*t. 12 = 30 + a*0.15, a = -120 m/s^2. F = M*a = (M1+M2)*a = 1500 * (-120) = -180,000 N. The negative sign means the force opposed the motion. 3. a = -120 m/s^2.

*October 20, 2016*

**Maths**

X = Smaller number. x+4x = 5x = Larger number. 5x-x = 24. X = 6, 5x = 30.

*October 19, 2016*

**physic**

Density = (80-25)g/500mL = 0.11g/mL.

*October 19, 2016*

**math**

X adults. 4x children. x + 4x = 300. X = 60 Adult seats. 4x = 4*60 = 240 Children seats.

*October 19, 2016*

**Math**

Cathy had $X. x - x/5 - x/4 - 120 = 540. x - 4x/20 - 5x/20 - 120 = 540, 20x - 4x - 5x - 2400 = 10,800, 11x = 13,200, X = $1200.

*October 18, 2016*

**Math**

The opposite angles are equal: A = C = 2x+25, B = D = 3x-5. 2(2x+25) + 2(3x-5) = 360. 4x+50 + 6x-10 = 360, X = 32. A = C = 64+25 = 89o, B = D = 96-5 = 91.

*October 18, 2016*

**physics**

a. M*g = 50 * 9.8 = 490 N. = Wt. of sled = Normal force(Fn). Fs = us*Fn = 0.3 * 490 = 147 N. Fap-Fs = M*a. Fap = M*0 + 147 = 147 N. b. Fk = uk*Fn = 0.10 * 490 = 49 N. Fap = M*0 + 49 = 49N.

*October 18, 2016*

**Physics**

V = Vo + a*t. 78 = 0 + a*0.04, a = 1950 m/s^2, F = M*a = 0.145 * 1950 = 283 N.

*October 18, 2016*

**Physics**

See previous post: Tue, 10-18-16, 4:43 AM.

*October 18, 2016*

**Physics**

M1V1 + M2V2 = M1V + M2V. 14866*5-14866*5 = 14866V+14866V, V = 0.

*October 18, 2016*

**Math**

a. L = 120yds * 3ft./yd = 360 Ft. W = 53 1/3yd * 3ft/yd = 160 Ft. b. Length = 2L + 2W = 2*360 + 2*160 = 1040 Ft. = Perimeter. c. 5,280Ft/mi * 1Lap/1040Ft = 5.1 Laps/m1. or 5.1 Laps = 1 mile.

*October 18, 2016*

**physics**

M1*V1 = M2*V2. 84*V1 = 28000*1, V1 = 333.3 mi/h.

*October 18, 2016*

**physics**

Fr = 25[120o] + 18[0o]. Fr = (25*Cos120+18) + (25*sin120)i. Fr = 5.5 + 21.65i = 22.3N[75.7o] = The resultant force. Fr is 75.7o N. of the 18N. force.

*October 18, 2016*

**physics**

PE = M*g * h = 63*9.8 * 7.6 = 4692 J. KE = 0.5M*V^2 = 0.5 * 63 * 3.2^2 = 323 J. 4692 - 323 = 4369 J. loss.

*October 17, 2016*

**physics**

Correction: Fap-Fs = M*a. Fap = M*0 + 150 = 150 N. = Force applied. Work = Fap*d = 150 * 7 = 1050 J.

*October 17, 2016*

**physics**

Fap-Fc-Fs = M*a. Fap-550-150 = M*0 = 0, Fap = 700 N. = Force applied. W0rk = Fap*d = 700 * 7.0 = 4900 J.

*October 17, 2016*

**8th pre algebra**

solve for x 2x-7=13 subtract 7 to both sides divide by 2 both sides x=10..am i right?

*October 17, 2016*

**MATH (Celcius/Fahrenheit)**

F = 1.8C + 32 = 1.8*15 + 32 =

*October 17, 2016*

**Physics**

A. = PE = Mg*h = 1.8*9.8 * 1.95 = B. PE = 1.8*9.8 * 1.55 =

*October 16, 2016*

**Physics**

h = 0.5g*t2 = 4.9*1.3^2 =

*October 16, 2016*

**Physics**

28o W. of N. = 118o CCW from +x-axis. 16o E. of N. = 74o CCW from +x-axis. T1*Cos118 = -T2*Cos74. T1 = -T2*Cos74/Cos118 = 0.587T2. T1*sin118 + T2*sin74 = -(-46), 0.883T1 + 0.961T2 = 46, 0.883(0.587T2) + 0.961T2 = 46, 0.518T2 + 0.961T2 = 46, T2 = 31.1 N. T1 = 0.587*T2 = 0.587*...

*October 16, 2016*

**maths fraction**

X pupils in class. X/2 girls in class. X/2 boys in class. 3/8 * X/2 = 3x/16 Girls wear glasses. 1/4 * X/2 = x/8 Boys wear glasses. 3x/16 + x/8 = 3x/16 + 2x/16 = 5x/16 Pupils wear glasses. (5x/16)/X = 5/16 of the pupils wear glasses. .

*October 16, 2016*

**Phyics**

V = 1.7m/s[41o]. d = 1.7m/s * 437s *sin41 = 487.4 m.

*October 15, 2016*

**Physics**

Disp. = 21 + 34m[32o]. Disp. = (21+34*Cos32) + (34*sin32)i = 49.8 + 18.0i. Disp. = sqrt(49.8^2+18^2)

*October 15, 2016*

**math**

Tan A = 5m/12m, A = 22.6o. Cos22.6 = 3.4/V, V = 3.68 m/min.

*October 15, 2016*

**science**

R. Density = 750/1000 = 0.75.

*October 15, 2016*

**math**

20-6(2+1) = 2.

*October 14, 2016*

**Physics**

M*g = 100 * 9.8 = 980 N. = Wt. of crate = Normal force(Fn). Fs = us*Fn = 0.4 * 980 = 392 N. = Force of static friction. The crate does not move, because the applied force is less than the fore of static friction(Fs).

*October 14, 2016*

**physics**

M*g = 93 * 9.8 = 911.4 N. = Wt. of firefighter. Mg-Fk = M*a. 911.4 - 710 = 98*a, a = ?. V = Vo^2 + 2a*d. 3.2 = 0 + 2a*d, d = ?.

*October 14, 2016*

**Physics**

See previous post: Fri, 10-14-16, 10:33 AM.

*October 14, 2016*

**Physics**

Given: Vx = 30 m/s., Vy = 53 m/s. 2A. Vx = 30 m/s. Vy = 53 + g*t = 53 - 9.8*4 = 13.8 m/s. 2B. Dx = Vx*t = 30 * 4 = 120 m. Dy = 13.8 * 4 = 55.2 m. 3A. h = 0.5g*t^2 = 4.9*6^2 = 176.4 m.

*October 14, 2016*

**Physics**

Vo = 12m/s[47]. Xo = 12*Cos47 = 8.18 m/s. Yo = 12*sin47 = 8.78 m/s. Xo*T = 40. 8.18*T = 40, T = 4.89 s. = Time in air. Y = Yo + g*Tr_. 0 = 8.78 - 9.8Tr, Tr = 0.896 s. = Rise time. Tr+Tf = 4.89. 0.896 + Tf = 4.89, Tf = 3.99 s. = Fall time. ha = Yo*Tr + 0.5g*Tr^2. ha = 8.78*0....

*October 13, 2016*

**Physics**

a. M*g = 20 * 9.8 = 196 N. = Wt. of crate = Normal(Fn). Fap-Fs = M*a. 75-Fs = 20*0 = 0, Fs = 75 N. = Force of static friction. us = Fs/Fn = 75/196 = 0.383. b. 60-Fk = M*a. 60-Fk = M*0 = 0, Fk = 60 N. uk = 60/196 = 0.306.

*October 13, 2016*

**Physics**

52o S. of E. = 308o CCW. Disp. = 77[21o] + 124[308o]. Disp. = (77*Cos21+124*Cos308) + (77*sin21+124*sin308)I = 148.2 - 70.11i = 164m1[-25.3o] = 25.3o S. of E. = Direction. The crew must fly 164 miles in a direction 25.3o S. of E.

*October 13, 2016*

**Physics**

0.5g*t^2 = 25. 0.83*t^2 = 25, t = 5.49 s. to reach gnd. h = 0.5g*t^2 =4.9*5.49^2 = 148 m.

*October 13, 2016*

**physics**

V^2 = Vo^2 + 2g*h = 23^2 - 19.6*14 =

*October 13, 2016*

**Physics 11**

Vp + 50i = 500[0o]. Vp = 500 - 50i = 503 km/h[-5.71o] = 5.71o S. of E. = Direction.

*October 13, 2016*

**Physics**

D1 = 88 * 2 = 176km, S. D2 = 55 * 1.5 = 82.5km[70o] N. of E. X = 82.5*Cos70 = 28.22 km. Y = -176 + 82.5*sin70 = -98.5 km. D = sqrt(X^2+Y^2) = sqrt(28.22^2+98.5^2) = 102.5 km. Tan A = Y/X = (-98.5)/28.22 = -3.49043, A = -74o = 74o S. of E. = Direction.

*October 13, 2016*

**physics grade 11**

Post the problem.

*October 13, 2016*

**Physics**

V = Vo + a*t = 0 + 2*6 = 12 m/s. V = Vo + a*t. 0 = 12 + a*4, a = -3 m/s^2.

*October 13, 2016*

**Physics**

Ek = 0.5M*V^2 = 500*490 = 245,000 J.

*October 13, 2016*

**Physics**

a. V^2 = Vo^2 + 2g*h = 0 + 19.6*5 = 98, V = 9.90 m/s. Ek = 0.5M*V^2 = 500*98 = 49,000 J. b. V^2 = Vo^2 + 2g*h. 0 = Vo^2 - 19.6*25, Vo = 22.1 m/s. Ek =

*October 13, 2016*

**Java Programming Algorithm Help**

I just realized that my example provided is not clear and wrong. How about "51.283" and "1.982" We know 51 - 1 = 50 and 0.982 - 0.283 = 0.699 BUT, 51.283 - 1.982 = 49.301 Thank you

*October 12, 2016*

**Java Programming Algorithm Help**

Ok so for my assignment, I have to have two String inputs. For example, "1.021" and "2.51" And I need to calculate the difference between these strings (biggest number minus smaller). I can only use the data types: short, char, boolen and String. I cannot ...

*October 12, 2016*

**Physics**

V = Vo + a*t(i) = 4.8 + 3.4i*4.4 = 4.8 + 14.96i = sqrt(4.8^2 + 14.960^2) = 15.71 m/s.

*October 11, 2016*

**physics**

V = Vo + a*t. 21 = 0 + a*7, a = 3 m/s^2. V = 0 + 3*2 = 6 m/s.

*October 11, 2016*

**math**

727.7cm^3 * 19.3g/cm^3 = 14,045 g. Wt. = 14,045g * 1Lb/454g = 30.9 Lbs.

*October 11, 2016*

**Physics**

a. 0.5g*t^2 = 100. 4.9t^2 = 100, t = 4.52 s. b. V = Vo + g*t = 0 + 9.8*4.52 = 44.3 m/s. = Velocity after falling 100 m. Vo*t + 0.5g*t^2 = 100. 44.3*t + 0.5g*t^2 = 100, 4.9t^2 + 44.3t - 100 = 0, Use Quadratic formula: t = (-B+-sqrt(B^2-4AC)/2A. t =(-44.3+-sqrt(44.3^2+1960)/9.8...

*October 11, 2016*

**Science**

X = t^2-4t+7. X = 4^2 - 4*4 + 7 =

*October 11, 2016*

**Physics**

Y^2 = Yo^2 + 2g*h. Yo = sqrt(Y^2-2g*h). So if each object has the same value of Y and h, their initial Y component of velocity would be equal. We have 3 variables: 1. Y = 0 = Vertical component of final velocity. 2. Yo = Vertical component of initial velocity. 3.The max height...

*October 11, 2016*

**physics**

M1*d1 = M2*d2. M1*1.2 = M2*1.5, M1 = 1.25M2. (M1+14)*1.8 = M2*3. (1.25M2+14)1.8 = 3M2, 2.25M2 + 25.2 = 3M2, M2 = 33.6 kg, F2 = M2*g = 33.6*9.8 = 329.3 N. = Wt. of the girl. M1 = 1.25M2 = 1.25*33.6 = 42 kg, F1 = 42*9.8 = 411.6 N. = Wt. of the boy.

*October 11, 2016*

**AP Physics**

M*g = 5*9.8 = 49 N. = Wt. of the box. Fp = 49*sin30 = 24.5 N. = Force parallel t0 the incline. T = Fp = 24.5 N.

*October 10, 2016*

**math**

sin A = a/c = 26/65.2 = 0.39877, A = 23.5o. A + B + C = 180. 23.5 + B + 90 = 180, B = 66.5o.

*October 10, 2016*

**alegbra 1**

Incomplete.

*October 10, 2016*

**physics**

V1*t = V2*t + d1. V1*t-V2*t = d1, t(V1-V2) = d1, t = d1/(V1-V2).

*October 10, 2016*

**Geometry**

86o + Xo + Yo = 180o. Yo = 180-86-X = 94-X.

*October 10, 2016*

**pre-calc**

r = 6-4 = 2mi/h.

*October 10, 2016*

**Science**

Vb = 12i + 20 = Sqrt(12^2+20^2) =

*October 10, 2016*

**physics**

M*g = 85 * 9.8 = 833 N. = Wt. of block. Fn = Mg-F*sin38 = 833 - 0.616F = Normal force. F*Cos38-u*Fn = M*a. 0.788F - 0.42(833-0.616F) = M*0 = 0, 0.788F - 349.9+0.259F = 0, 1.047F = 349.9, F = 334.3 N.

*October 9, 2016*

**physics**

1. Vr = Vc + Vb = 4. -3i + Vb = = 4, Vb = 4 + 3i = 5km/h[36.9o]. Direction = 36.9o N. of E. 2. Vr = 4 km/h. = Resultant velocity. 3. 5km/h[36.9o].

*October 9, 2016*

**physics**

V^2 = Vo^2 + 2a*d. 0 = 22.5^2 + 2a*41, a = ?. "a" will be negative which means that the acceleration opposes the motion. F = M*a = 1240*a.

*October 9, 2016*

**physics**

M*g = 350 N. Fn = Mg-Fap*sin42 = Normal force. Fn = 350-250*sin42 = Fap*Cos42-Fk = M*a. 250*Cos42-Fk = M*0 = 0, Fk = ?. u = Fk/Fn.

*October 9, 2016*

**physics**

M*g = 80 * 9.8 = 784 N. = Wt. of cabinet = Normal force(Fn). Fk = u*Fn. 300 = u*784, u = ?.

*October 9, 2016*

**math**

T = t1*t2/(t1+t2).

*October 9, 2016*

**physical**

Work = F*d =

*October 8, 2016*

**physics**

M = 300Lbs * 0.454kg/Lb = 136.2 kg. Fk = u*Fn = u*Mg = 0.04 * (136.2*9.8) = 53.4 N. = Force of kinetic friction. Fap-Fk = M*a. Fap-53.4 = M*0 = 0, Fap = 53.4 N. = Force applied.

*October 8, 2016*

**physisc**

h = 145 m ?.

*October 8, 2016*

**Physics**

12*I = 60, I = 5A. A*h = 80, 5*h = 80, h = 16.

*October 8, 2016*

**Physics**

20*Log(Ns/Np) = 13. Log(Ns/Np) = 13/20 = 0.65, Ns/Np = 10^0.65 = 4.47. Ns = 4.47Np.

*October 7, 2016*

**physics**

k = 3kg/12cm = 0.25 kg/cm. d = 4kg * 1cm/0.25kg = 16 cm. Or d = (4kg/3kg) * 12cm = 16 cm.

*October 7, 2016*

**Physics**

Hydrogen.

*October 7, 2016*

**physics**

T = M*g + M*a = M(g+a) = 8000*11.2 =

*October 7, 2016*

**Physics**

1. -T1*Cos60 = -T2*Cos45. T1 = -T2*Cos45/-Cos60 = 1.41T2. T1*sin60 + T2*sin45 = -(-150). 0.866T1 + 0.707T2 = 150, 0.866*(1.41T2) + 0.707T2 = 150, 1.225T2 + 0.707T2 = 150, 1.93T2 = 150, T2 = 77.7 N. T1 = 1.41 * 77.7 = 109.9 N.

*October 7, 2016*

**math**

X birds. Y dogs. Eq1: x + y = 30. Eq2: 2x + 4y = 86. Multiply Eq1 by -4: -4x - 4y = -120 +2x + 4y = 86. Sum: -2x = -34, X = 17 birds.

*October 6, 2016*

**physics**

V = Vo + a*t. 3 = 7 + a*3, a = - 1.333 m/s^2. F = M*a = 5 * (-1.33) = -6.67 N. The negative sign means that the force opposes the movement of the object.

*October 6, 2016*

**Trig**

Tan A = 5(Q3), A = 78.7o. S. of W. = 180+78.7 = 258.7o CCW. Sin B = 2/3(Q2), B = 41.8o N. of W. = 180-41.8 = 138.2o CCW. A-B = 258.7 - 138.2 = 120.5o, Q2.

*October 6, 2016*

**physics**

V = Vo + a*t. 12.4 = 39.3 - 2.8t, t = ?. Since the velocity is decreasing, the acceleration is negative.

*October 6, 2016*

**physics**

M1*d1 = M2*d2. d1 = M2*d2/M1 = 600*d2/500 = 1.2d2. d1 + d2 = 22. 1.2d2 + d2 = 22, d2 = 10 m. From its' end. d1 = 1.2d2 = 1.2*10 = 12 m. From its' end.

*October 6, 2016*

**physics**

L = Sqrt(X^2+Y^2) = Sqrt(2^2 + 13^2) =

*October 6, 2016*

**physics**

d = Vo*t + 0.5*t^2. 12 = 10*t + 2t^2, 2t^2 + 10t - 12 = 0. t^2 + 5t - 6 = 0. (t-1)(t+6) = 0, t-1 = 0, t = 1 s. t+6 = 0, t = -6. Solution: t = 1 s.

*October 6, 2016*

**Physics**

Work = F*d = Mg * d = 0.065*9.8 * 2.3 =

*October 5, 2016*

**Physics**

h = Vo*t + 0.5g*t^2. h = 120*4 - 4.9*4^2 =

*October 5, 2016*

**Physics**

d = 0.5a*t^2.

*October 5, 2016*

**Business Finance**

See previous post: Wed, 10-5-16, 7:27 PM.

*October 5, 2016*

**Business Finance**

P = Po(1+r)^n. Po = $3500. r = 0.05/2 = 0.025. n = 2Comp./yr. * 5yrs. = 10 Compounding periods. P = ?.

*October 5, 2016*

**Physics**

F1 = 100*Cos60 = 50 N.

*October 5, 2016*

**Science homework**

Incomplete.

*October 5, 2016*

**Science**

Incomplete.

*October 5, 2016*

**College Physics**

Incomplete.

*October 5, 2016*

**alegebra**

(1.08*10^-3) * (9.3*10^-3) = 10.044*10^-6 = 1.0044*10^-5.

*October 4, 2016*

**Maths**

A. 58 * t + 32 * t = 900 km. 90t = 900, t = 10 Hours. B. V1 = 58km/h = 58,000m/3600s = 16.11 m/s. V2 = 32km/h = 32,000/3600s = 8.89 m/s. V1*t + V2*t = 900 m. 16.11t + 8.89t = 900, t = 36 s.

*October 4, 2016*

*****

V = pi*r^2*h. 37000 = 3.14*25^2*h, h = ?.

*October 4, 2016*

**Maths**

d1 = r*t = 8 * (5*60) = 2400 m. d2 = 6 * (5*60) = 1800 m. d1-d2 = 2400 - 1800 = 600 m. Apart.

*October 4, 2016*

**Physics**

d = r*t = 340 * (0.1/2) = 17 m.

*October 4, 2016*

**Physics**

Vo = 52m/s[28o]. Xo = 52*Cos28 = 45.91 m/s. Yo = 52*sin28 = 24.41 m/s. a. Y^2 = Yo^2 + 2g*h. 0 = (24.41)^2 - 19.6h, h = ?. b. Range = Vo^2*sin(2A)/g. A = 28o, Range = ?.

*October 4, 2016*