Monday

April 21, 2014

April 21, 2014

Total # Posts: 8,522

**physics**

T= F = m*a = 454 * 3.51 = 1594 N.

**physics, buoyance**

A. Hb=(Do/Dw)*Ho=(730/1000)*0.2=0.146 m Below the the water. Ha = 0.2 - 0.146 = 0.054 m Above water. B.Mc=V*D = 0.2^3m^3 * 730kg/m^3=5.84 kg. = Mass of cube. (Mc+Mo)/Vc = Dw(Density of water). (5.84+Mo)/0.008 = 1000kg/m^3 5.84 + Mo = 8 Mo = 2.16 kg = Mass of object to be added.

**Physics**

See previous post: Tue,12-3-13,10:36 PM.

**physics**

Vc = 46.4mi/3600s * 1600m/mi = 20.62 m/s Circumference=pi*2r=3.14 * 0.568=1.784 m Period =(1.784m/20.62m)*1s. = 0.0865 s.

**Math**

a. x = 3 x-3 = 0 x = -1 x+1 = 0 x = -5 x+5 = 0 Y = (x-3)(x+1)(x+5) = 0 Multiply the 1st two parenthesis: Y = (x^2-2x-3)(x+5) = 0 Eq: Y = x^3 + 3x^2 -13x - 15 = 0

**Physics**

See previous post: Tue,12-3-13,10:36 PM.

**brief calc**

2q/3 = 8-p2q/3 = 8-6 = 2 2q/3 = 2 2q = 6 q = 3

**brief calc**

q = 130 2*11 = 108.

**physics**

I=V/(Ro+Ra) = 10/(1k+0.05k) = 9.5238 mA. = Measured current. I=10/1k = 10.00 mA=Theoretical current. Accuracy = ((10.00 - 9.5238)/10)*100%4.762 %.

**Physics**

At top of hill: KE + PE = mg*h 0 + PE = mg*h PE = mg*h At bottom of hill: KE + PE = mg*h KE + 0 = mg*h KE = mg*h = 0.5m*V^2 0.5m*V^2 = mg*h V^2 = 2g*h V = Sqrt(2g*h). V = Sqrt(19.6*h). Sqrt means Square root.

**physics**

See previous post.

**physics**

Fc = m*g = 29kg * 9.8N/kg = 284.2 N. = Force of crate. Fap-Fs = m*a 90-u*Fc = m*0 90 - u*284.2 = 0 u*284.2 = 90 us = 0.317

**math**

T = (2/5) * 2 = 4/5 or 0.8 h.

**Physics**

a. a=F/m = 3.34*10^7/2.77*10^6 = 12.06 m/s^2. b. t = 2.5min * 60s/min = 150 s. h = 0.5a(2t-1) h = 6.03*(300-1) = 1803 m.

**Maths**

100% - 40.25% - 30.76% = 28.99 % Greater than 5.5 Ft. People = 0.2899 * 120M=34.79 M Greater than 5.5 Ft.

**science**

P = 40.2hp * 746W/hp = 29,989 Watts. = 29,989 Joules/s. T = 5.9*10*5J/(2.9989*10^4J/s=19.67 s.

**Physics**

B. L = V/F = 343/239.7 1.43 When flying away.

**Physics**

A. L = V/F = 343/258 = 1.33 m. B. F = ((Vs+Vr)/(Vs-Vg))*Fo = 258 Hz ((343+0)/(343-12.6))*Fo = 258 (343/330.4) * Fo = 258 1.0381Fo = 258 Fo = 248.5 Hz=Initial Freq. of the goose F = ((343-0)/(343+12.6))*248.5 F = (343/355.6) * 248.5 = 239.7 Hz When flying away.

**Physics**

A. L = V*T =V*(1/F)=V/F L = 343/4.4*10^6 = 7.95*10^-5m. B. L = 1580/4.4*10^6 = 359*10^-6=3.59*10^-4 m.

**math **

what property is described in this equation: 24x5=(20x5)+(4x5)

**Physics**

Fs = m*g = 87.1kg * 9.8N/kg = 853.6 N. = Force of snowboarder. Fp = 853.6*sin36.7 = 510.1 N. = Force parallel to hill. Fn = 853.6*cos36.7 = 684.4 N = Normal = Force perpendicular to hill. Fk = u*Fn = 0.106 * 684.4 = 72.55 N. = Force of kinetic friction. a=(Fp-Fk)/m=(510.1-72.5...

**Algebra**

x^2 + y^2 + 8x + 2y + 8 = 0 x^2+8x+(8/2)^2+y^2+2y+(2/2)^2=-8+(8/2)^2 +(2/2)^2. x^2+8x+16 + y^2+2y+1 = -8+16+1 Eq: (x+4)^2 + (y+1)^2 = 9 C(-4,-1). r2 = 9 r = +-3

**Geometry**

See previous post: Mon,12-2-13,7:39 AM.

**Geometry**

See previous post:Mon,12-2-13,7:39 AM.

**Geometry**

The diagonals form 2 30o-60o rt. triangles. h = 24*sin30 = 12 In. W = 24*cos30 = 20.8 In. P = 2*(W+h) = 2*(20.8+12) = 65.6 In.

**physics**

v = Vmax*sinWt v = 100*sin(1000t) Vrms = 0.707 * 100 = 70.7 Volts. W = 2pi*F = 1000 6.28*F = 1000 F = 159 Hz. Xl = W*L = 1000 * 0.5 = 500 Ohms. Xc=1/W*C=1/(1000*4.6*10^-6)=-217.4 Ohms tan A = (Xl+Xc)/R tanA = (500+(-217.4))/400 = 0.7065 A = 35.2o Z = R/cos A = 400/cos35.2 = 48...

**physics**

h = Vo*t + 0.5g*t^2 = 20 37.8t _ 4.9t^2 = 20 -4.9t^2 + 37.8t - 20 = 0 Use Quadratic Formula and get: t = 0.571, and 7.14 s. So, when the ball is rising; it reaches 20 m in 0.571 s. When it is falling, it reaches 20 m in 7.14 s.

**physics**

See your previous post: Sun,12-1-13,10:34 PM.

**physics**

See previous post: Fri,11-29-13,8:15 PM.

**physics. again.**

V== Vo + g*t = 10 m/s. 37.8 + (-9.8)t = 10 -9.8t = 10-37.8 =-27.8 t = 2.84 s. h = Vo*t + 0.5g*t^2 h = 37.8*2.84 - 4.9*2.84^2 = 67.83 m.

**physics**

Fs = m*g = 22kg * 9.8N/kg = 215.6 N. = Force of the sled. Fp = 215.6*sin6 = 22.54 N. = Force parallel to the incline. Fn = 215.6*cos6 = 214.4 N. = Normal = Force perpendicular to the incline. Fk = u*Fn = 0.2 * 214.4 = 42.88 N. = Force of kinetic friction. V = 64km/h = 64000m/3...

**5th grade math**

I'm glad I could help, and thanks for your response.

**5th grade math**

4th Grade: 9 Left-handed students. Total = 3 * 9 = 27 Students. 9/27 = 1/3 Are left-handed. 5th Grade: 7 Left-handed students. Total = 30-2 = 28 Sudents. 7/28 = 1/4 Are left-handed. 6th Grade: 6 Left-handed students. Total = 27+3 = 30 Students. 6/30 = 1/5 Are left-handed. The ...

**Physics**

r2 = r1 + a*(T-To)r1 = 4.42 cm. 4.40 + 1.3*10^-4(T-20)4.40 = 4.42 4.40 + 5.72*10^-4(T-20) = 4.42 5.72*10^-4(T-20) = 4.42-4.40 = 0.02 5.72*10^-4T - 114.4*10^-4 = 0.02 5.72*10^-4T = 0.02 + 0.01144 = 0.03144 T = 314.4*10^-4/5.72*10^-4 = 54.97o

**Math**

Same procedure as previous post: Sun,12-1-13,7:39 PM.

**Math**

Given: A(-8,3), B(-6,1). m = -1 A(-8,3), P(x,y). m== -1. m = (y-3)/(x-(-8)) = -1 m = (y-3)/(x+8) = -1 Cross multiply: y-3 = -1(x+8) y-3 = -x-8 Eq: x + y = -5 Or x + y +5 = 0 Replace y with 0: x + 0 = -5 X = -5 = X-intercept. Replace X with 0: 0 + y = -5 Y = -5 = y-int.

**Physics**

Wr = m*g = 0.5kg * 9.8N/kg = 4.9 N = Wt. of the rat. Fp = 4.9*sin34 = 2.740 N. = Force to the plane. Fn = 4.9*cos34 = 4.062 N. Normal = Force perpendicular to the plane. Fk = u*Fn = 0.2 * 4.062 = 0.8125 N. Fc-Fp-Fk = m*a 0.4-2.74-0.8125 = m*a m*a = -3.15 a = -3.15/m = -3.15/0...

**Physics**

Fex = 15000 N. ? m = 500kg a = Fex/m = 15000/500 = 30 m/s^2.

**physics**

Change in L = Lo * a*(T-To) = 65.1 * 10^-5 * (-31.2-15.8) = -0.030597 m.

**physics**

Fap*cos45-u*mg = m*a Fap*cos45-0.02*588 = m*0 = 0 Fap * cos45 - 11.76 = 0 Fap*cos45 = 11.76 N. = Hor. component of Force applied. Work = 11.76 * 1000. = 11,760 Joules.

**physics**

a. Xl = 2pi*F*l = 6.28*50*0.405=127.2 Ohms Xc = 1/(6.28*50*4.43*10-6) = -718.9 Ohms tan A = (Xl-Xc)/R tan A = (127.2-718.9)/400 = -1.47925 A = -55.94o Z=R/cosA = 400/cos(-55.94) = 714.2 Ohms[-55.94o]= The Impedance. Vmax = Imax * Z=0.25 * 714.2 =178.6 Volts. b. The negative im...

**physics**

Fn = 75N[40o] + 85N[340o] X = 75*cos40 + 85*cos340 = 137.3 N. Y = 75*sin40 + 85*sin340 = 19.14 N. tan A = Y/X = 19.14/137.3 = 0.13940 A = 7.94o Fn=X/cosA = 137.3/cos7.94=138.6 N[7.94o]

**PHYSICS**

a. Xc = 1/2pi*F*c Xc = 1/(6.28*60*4*10^-6) = 663.5 Ohms. I = V/Xc = 120/663.5 = 0.181A rms. b. Same procedure as "a".

**Physics**

We need to know the length of the hill. Length = 100 m? A = 30o m = 75 kg h = 100*sin30 = 50 m. = Ht. of hill. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*50 = 980 V = 31.3 m/s At bottom of hill. V^2 = Vo^2 + 2a*d a=(V^2-Vo^2)/2d=(31.3^2-0)/200=4.9 m/s^2 V = Vo + a*t = 31.3 0 + 4.9*t = 3...

**math**

CORRECTION: Cost = 2375*0.85*0.80*0.80 = $1292. Discount = 2375 - 1292 = $1083.

**math**

Discount = 2375*0.15*0.20*0.20 = $14.25

**Physics**

V1 = 6N[180o] X1 = -6N Y1 = 0 V2 = 4.5N[45o] X2 = 4.5*cos45 = 3.18 N. Y2 = 4.5*sin45 = 3.18 N. X = X1 + X2 = -6 + 3.18 = -2.82 N. Y = Y1 + Y2 = 0 + 3.18 = 3.18 N. tan Ar = Y/X = 3.18/-2.82 = -1.12766 Ar = -48.43o = Reference angle. A = -48.43 + 180 = 131.6o R=Y/sinA = 3.18/sin...

**Finance - Annuities**

P = Po*(1+r)^n P = $2250/mo. * 48mo. = $108,000 r = (3%/12)/100% = 0.0025 = Monthly % rate expressed as a decimal. n = 1comp./mo * 48mo = 48 Compounding periods. a. P = (Po-12000)*(1.0025)^48 = 108,000 (Po-12000)*1.12733 = 108000 Po-12000 = 95,801.75 Po = $107,801.75 = Initial...

**math**

A*(1-0.0653) = 1,225,000 A*0.9347 = 1225000 A = 1,310,580.94

**physics**

F1 = m*g = 1.6kg * 9.8N/kg = 15.68 N F2 = (0.05m/1m) * 400N = 20 N. F1-Fs = m*a 15.68-Fs = m*0 = 0 Fs = 15.68 = Force of static friction. Fs = u*F2 = 15.68 u*20 = 15.68 u = 0.784 = Coefficient of static friction.

**Physic: Projectile Motion**

Range = Vo^2*sin(2A)/g = 15 m. Vo^2*sin(40)/9.8 = 15 Vo^2*0.0656 = 15 Vo^2 = 228.7 Vo = 15.12 m/s.

**Math**

2. A cube has 6 edges. As = 6 * 3^2 = 6 * 9 = 54 Sq. In.

**finance**

1. P = (Po*r*t)/(1-(1+r)^-t) r = (9%/12)/100% = 0.0075 = Monthly % rate expressed as a decimal. t = 12mo/yr * 5yrs. = 60 Months. Plug th above values into the givenEq and get: P = $12,455.01 I = P-Po 2. Monthly = P/t 3. P = Po + Po*r*t Po = $10,000 r = 0.0075 t = 60 Months Plu...

**physics**

Fap-Fk = m*a 30-Fk = 2 * 10 = 20 Fk = 30-20 = 10 N. = Force of kinetic friction.

**geometry**

See Related Questions: Thu,5-25-11,11:28 AM.

**Science, Physics, math, calculus**

a. h = 0.5g*t^2 = 0.77 4.9t^2 = 0.77 t^2 = 0.1571 t = 0.396 s. = Fall time. Dx = Xo * t = 5.15 m. Xo * 0.396 = 5.15 Xo = 13 m/s = Break speed. b. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*0.77 = 15.09 V = 3.88 m/s

**Physics**

h = 0.5g*t^2 = 50 m. 4.9t^2 = 50 t^2 = 10.2 Tf = 3.19 s. = Fall time. d = V*Tf = 100m/s * 3.19s = 319 m.

**PHYSICS**

CORRECTION: T = 1.15 Milliseconds.

**PHYSICS**

CORRECTION: d. Vr = I*R = (0.8*0.857)*7 = 4.8 Volts Vi=6-4.8=1.2 Volts across the inductor. V/e^(T/0.714) = 1.2 6/e^(1.40T) = 1.2 e^1.40T = 6/1.2 = 5 1.40T*Ln e = Ln 5 1.40T = 1.609 T = 1.15 s. 7 =

**PHYSICS**

a. T.C.=L/R=5.0/7=0.714 Milliseconds b. T/TC = 0.25mS/0.714mS = 0.350 Vi = V/e^(T/TC) = 6/e^0.350 = 4.23 Volts after 250 uS. I=Vr/R = (V-Vi)/R = (6-4.23)/7= 0.253A. c. I=Vr/R = (V-Vi)/R = (6-0)/7 = 0.857A d. Vr=I*R = (0.8*0.857)*7 = 4.80 Volts. Vi = 6-4.8 = 1.2 Volts. = Voltag...

**Math**

Incomplete.

**physics**

Fr = 975N[0o] + 745N[60o] + 1175N[90o] X=975 + 745*cos60 + 1175*cos90=1347.5 N Y = 745*sin60 + 1175*sin90 = 1820.2 N. tan A = Y/X = 1820.2/1347.5 = 1.31079 A = 53.5o Fr = Y/sin A = 1820.2/sin53.5=2264.3 N. [53.5o].

**physics**

Ht. = 50 m.? a. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*50 = 980 V = 31.3 m/s. b. V = Vo + g*t = 31.3 m/s. 0 + 9.8t = 31.3 t = 3.19 s. c. m = 2.0Lb * 0.454kg/Lb = 0.908 kg. KE = m*V^2/2 = 0.908*31.3^2/2 = 444.8 J.

**physics**

Ws = m*g = 77.7kg * 9.8N/kg = 761.5 N = Wt. of skier. Fp = 761.5*sin35.7 = 444.3 N. = Force parallel to slope. Fn = 761.5*cos35.7 = 618.4 = Normal = Force perpendicular to slope. Fk = u*Fn = 0.08 * 618.4 = 49.47 N. = Force of kinetic friction. Fp-Fk = m*a a=(Fp-Fk)/m=(444.3-49...

**science**

KE = 0.5m*V^2 = 2.5*4^2 = 40 J.

**Please help!- Physics**

d = 483[180o ] + 347[106o] + 347[106o] d = 483[180 + 694[106o] X = 483*cos180 + 694*cos106 = -674.3 km Y = 483*sin180 + 694*sin106 = 667.1 km tan Ar = Y/X = 667.1/-674.3 = -0.98935 Ar = -44.69o = Reference angle. A = 180-44.69 = 135.3o d = X/cosA = -674.3/cos135.3 = 948.7 km [...

**Math**

Incomplete.

**physics**

3.2 cm from equilibrium position: KE + PE = mg*d 0 + PE = mg*d/2 Halfway to the equilibrium position: KE + PE = mg*d mg*d/2 + mg*d/2 = mg*d KE = mg*d/2 = 0.5m*V^2 0.5m*V^2 = mg*d/2 = 3.92*0.032/2 0.2*V^2 = 0.06272 V^2 = 0.3136 V = 0.56 m/s.

**Physics**

CORRECTION: V = 81.6km/h[74.93o] D = 245 km[74.93o]

**Physics**

V = 100km/h[90o] + 30km/h[315o] X = 100*cos90 + 30*cos315 = 21.21 km/h Y = 100*sin90 + 30*sin315 = 78.79 km/h tan A = Y/X = 78.79/21.21 = 3.71461 A = 74.93o V=Y/sinA = 78.79/sin74.93=81.6 km/h [78.79] D=V*t = 81.6[78.79] * 3 = 245 km[78.8o]

**Math**

Parallel lines have equal slopes.

**Math**

Parallel lines have equal slopes.

**Math**

Parallel lines have equal slopes.

**Math**

2x - 3 = 4y Eq1: 2x - 4y = 3 m1 = -A/B = -2/-4 = 1/2 m2 = -(2/1) = -2 Y = mx + b Eq2: Y =-2x - 5/4.

**Math**

See previous post: Wed,11-20-13,6:18PM.

**Math**

Eq1: x + 2y = 10. m1 = -A/B = -1/2 The slope of the 2nd line = the negative reciprocal of m1: m2 = -(-2/1) = 2. Y = mx + b Eq2: Y = 2x - 10 or 2x - y = 10

**physics**

Energy = 120 * 5 *6h /1000=3.6 KWh Used Cost = 3.6kwh * 0.090/kwh = 0.324 or 32.4 Cents.

**Physics**

L = h/sin A = 2/sin 30 = 4 m. = Length of incline. KE = mg*h-Fk*L 0.5m*V^2 = mg*h-Fk*l 0.2*4.50^2 = 3.92*2 - Fk*4 4.05 = 7.84 - 4Fk 4Fk = 7.84-4.05 = 3.79 Fk = 0.948 N. = Force of kinetic friction.

**physics**

Fn = m * a =47 * 4.50

**Physics**

Yes. For a given initial velocity, the larger the angle the greater the vertical component of initial velocity. The increase in vertical velocity causes an increase in the max. ht.

**Physics - projectile**

V = Vo = 50 m/s.

**Physics**

b. h = Vo*t + 0.5g*t^2 = 3.05 8t + 4.9t^2 - 3.05 = 0 Use Quadratic Formula and get: t = 0.319 s. c. V^2 = Vo^2 + 2g*h V^2 = 8^2 + 19.6*3.05 = 123.78 V = 11.13 m/s.

**MATH**

A. Y = ho - 8X ho = The initial ht. B. When he got on the elevator, it was at the initial height(ho) and decreased at a rate of 8 feet per second for 12 seconds. C. Y = ho _ 8x = 240 Ft. ho - 8*12 = 240 ho = 240 + 96 = 336 Ft. above gnd. D. Y = 336 - 8x = 0 336 - 8x = 0 8x = 3...

**math**

N = 0.57 * 11

**Physics**

d = 0.5g*t^2 = 75 4.9t^2 = 75 t^2 = 15.31 Tf = 3.912 s. = Fall time. d = V*Tf = 7-4 = 3 m. V * 3.912 = 3 V = 0.769 m/s.

**math**

Did your book give the total # of Robinsons? Something is missing.

**physical science**

P = F * d/t = 96 * 2.8/4.6 = 58.43 J/s = 58.43 Watts.

**college algebra**

4^(x-3) = 3^(2x) (x-3)*Log4 = 2x*Log 3 Divide both sides by Log 4: x-3 = 2x * 0.79248 = 1.5850x x - 1.5850x = 3 -0.5850x = 3 X = -5.1282

**science**

Magnitude = 210 N. Direction = 30o South of West = 210o CCW.

**science**

Magnitude = 200 N. Direction = 60o North of East = 60o CCW.

**science**

Magnitude = 125 N. Direction = North(Positive Y-axis).

**math**

Sally has X postcards. Marta has X postcards. X = 4(X-18) Solve for X.

**Math**

Y = 5 For all values of X. (0,5),(5,5),(2,5),(-3,5).

**science**

500+(65-47)sk/wk*105days*1wk/7days=770 Skunks.

**Phyics**

d1 = 0.5a*t^2 = 15 m. 0.5*t^2 = 15 t^2 = 30 T1 = 5.477 s. V = a*t = 1m/s^2 * 5.477s = 5.477 m/s. d2 = V * t = 5.477m/s * 15s = 82.2 m. D = d1 + d2 = 15 + 82.2 = 97.2 m. = Distance at which he was caught. T = T1 + T2 = 5.477 + 15 = 20.48 s To catch up.

**math**

(25%/15%/10% = (1-0.25)(1-0.15)(1-0.10)= 0.75 * 0.85 * 0.90 = 0.57375

**math**

a. X + 27.80*20 = 914 X = $358. b. C = 358 + 27.80x X = The number of years since 1981. c. 2000-1981 = 19 years. C = 358 + 17.80*19 = $528.20

**Check my answers please- Physics**

1. A force that makes the net force on an object 0. 2. It is equal in magnitude and opposite in direction. 3. An object in equilibrium must not be in motion. 7. 90 N.

**algebra2**

See previous post: Mon,11-18-13,11:59 AM.

**algebra2**

CD: $X Savings: $4X Mutual: $(15,000-5X) 0.02X + 0.01*4X + 0.1(15000-5x) = 210 0.06X + 1500 - 0.5X = 210 -0.44X = 210-1500 = -1290 X = 2931.82 4X = 4*2931.82 = $11,727.27 = Savings.

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