Thursday

February 26, 2015

February 26, 2015

Total # Posts: 10,138

**Math**

V = pi*r^2 * L = pi * (0.5/12)^2 * 12 = 5.45*10^-3 Ft^3. = Vol. of rod. Wt.=490Lbs/Ft^3 * 5.45*10^-3Ft^3 = 2.67 Lbs.
*April 30, 2014*

**physics**

d = V*t = 343m/s * (1.6s/2) = 274.4 m.
*April 30, 2014*

**Science**

g on Jupiter is 2.5 times g on earth. 100/2.5 = 40 Lbs.
*April 30, 2014*

**physics**

What direction is the airplane flying?
*April 30, 2014*

**Science**

F = m*a = 5 * 7 = 35 N.
*April 29, 2014*

**Engineering**

Was the current given?
*April 29, 2014*

**Physics**

100 Cars: db = 10*Log(I/Io) db = 10*Log(I/10^-12) = 80 Log(I/10^-12) = 8 10^8 = I/10^-12 I = 10^-4 W/m^2. 5 Cars: I = (5/100) * 10^-4 = 5*10^-6 W/m^2. db = 10*Log(5*10^-6/10^-12) db = 10*Log(5*10^6) = 67.
*April 29, 2014*

**Govt college of technology**

Correction: Change 6 cm to 12 cm. The results does not change.
*April 29, 2014*

**Govt college of technology**

Circumference = pi*2r = pi * 6cm = 37.7 cm d = 300rev/min * 37.7cm/rev * 0.5min = 18.85 cm. Note: 0.5 min = 30 sec.
*April 29, 2014*

**Science**

F = m * a
*April 29, 2014*

**Math -Help**

X Crocus bulbs. Y Daffodil bulbs. Eq1: X + Y = 100 Eq2: 0.45x + 0.85y = $55.80 Multiply Eq1 by (-0.85) and add the Eqs: -0.85x - 0.85y = -85 +0.45x + 0.85y = 55.80 Sum: -0.40x = -29.2 X = 73 In Eq1, replace X with 73: 73 + Y = 100 Y = 27
*April 29, 2014*

**Math! Helppppp**

Two rt. triangles are formed with the ropes representing 7he hyp. of the triangles. The smaller Triangle: m = TanA = Y/X = 8/16 = 0.50 The Larger Triangle: m = TanA = Y/X = 16/16 = 1.00
*April 29, 2014*

**Physics**

Vo = 41.8m/s[30o] Xo = 41.8*cos30 = 36.2 m/s. Yo = 41.8*sin30 = 20.9 m/s. Y = Yo + g*Tr = 0 @ max. ht. Tr = -Yo/g == -20.9/-9.8 = 2.13 s. = Rise time. Tf = Tr = 2.13 s. = Fall time. Range = Xo*(Tr+Tf) = 36.2m/s * 4.26s = 154.4 m.
*April 29, 2014*

**Physics**

Correction: Change Tf = Yr to Tf = Tr.
*April 29, 2014*

**Physics**

Vo = 70m/s[15o] Xo = 70*cos15 = 67.61 m/s. Yo = 70*sin15 = 18.12 m/s. a. Y = Yo + g*Tr = 0 @ max ht. Tr=-Yo/g = -18.12/-1.63 = 11.12 s.=Rise time. Tf = Yr = 11.12 s. = Fall time. Tr+Tf = 11.12 + 11.12 = 22.24 s. = Time in flight. b. Range = Xo * (Tr+Tf) = 67.61 * 22.24 = 1504 m.
*April 29, 2014*

**physics**

Vc = Vo + a*(T-To)Vo Vc=548 + 12*10^-6*(10)*548 = 548.06576 cm^3 = Volume of container after 10oC increase in temperature. V = 548 + 7*10^-4*(10)*548 = 551.836 cm^3. = Volume of the oil after a 10oC increase in temperature. Vs = 551.836 - 548.06576 = 3.77 cm^3 = Volume spilled.
*April 28, 2014*

**Math Help**

Where is the Eq?
*April 28, 2014*

**physics**

Correction: Change V^@ to V^2.
*April 28, 2014*

**physics**

V^@=Vo^2 + 2g*h = 0 + 19.6*7.15 = 140.14 V = 11.84 m/s.
*April 28, 2014*

**Physics**

See Fri,5-2-14,2:17 AM post.
*April 28, 2014*

**Math 120**

T1 = Time for stone to hit bottom. T2 = Time for sound to reach top of well T1 + T2 = 17 s. T1 = 17-T2 0.5g*(17-T2)^2 = Vs*T2 4.9(289-34T2+T2^2) = 343T2 1416-167T2+4.9T2^2 = 343T2 4.9T2^2-510T2+1416 = 0 Use Quadratic formula and get: T2 = 2.85 s. T1 = 17-2.85 = 14.15 s. d = Vs...
*April 27, 2014*

**Physics**

Va = Ia*Ra = 2*10^-3 * 50 = 0.10 Volts = Voltage across ammeter @ full-scale. Rp=Va/I = 0.1/(40-2)*10^-3=0.1/38*10^-3= 2.632 Ohms. = Resistor connected in parallel with the ammeter to extend current range to 40 mA. Voltmeter: Rs = (V-Va)/If = (14-0.10)/2*10^-3=6,950 Ohms = The...
*April 27, 2014*

**science**

F = m*a
*April 25, 2014*

**physics**

No, the mass does not change. Yes, they weigh less on the moon; because g is 9.8 on earth but only 1.63 on the moon.
*April 25, 2014*

**physics**

Mass = 0.45kg/Lb * 160Lbs. = 72 kg. Wt. = m*g = 72kg * 9.8N./kg = 705.6 N. on Earth. Wt. = 705.6N/6 = 117.6 N. on the moon.
*April 25, 2014*

**finance**

Compounded Annually? P = Po(1+r)^25 = 45,000(1+0.07)^25 = $244,234.47 Simple Interest: P = Po + Po*r*t = 45,000 + 45000*0.07*25 = $123,750.
*April 24, 2014*

**science**

a = 3m/s^2 = (3m/s)/s.
*April 24, 2014*

**math**

P = Po(1+r)^n PO = $1,000 r = (8%/4)/100% = 0.02 n = 4comp./yr. * 1yr. = 4 Compounding periods. Plug the above values into the given Eq and solve for P. I = P-Po
*April 24, 2014*

**Physics ATTENTION HENRY!**

a.V^2 = X^2 + Y^2 = 0.8^2 + 1.2^2 = 2.08 Vs = 1.442 m/s. = Resultant velocity of the swimmer. Tan A = 0.8/1.2 = 0.66667 A = 33.7o E. of N.(N33.7E). d1 = 550m/cos33.7 = 661.1 m[N33.7E] = Dist. to other side. T1 = d1/Vs = 661.1/1.442 = 458.5 s. To reach other side. d2 = 550*Tan ...
*April 24, 2014*

**math**

P = Po(1+r)^n r = (14%/2)/100% = 0.07 = Semi-annual % rate expressed as a decimal. n = 2comp./yr. * 2.5yrs. = 5 Compounding periods. P = Po(1+0.07)^5 = $20,000 Po = 20000/1.07^5 = $14,259.72 I=P-Po = 20,000 - 14,259.72 = $5,740.28
*April 24, 2014*

**math**

See previous post: Thu,4-24-14,6:24 AM.
*April 24, 2014*

**math**

Same procedure as your 6:24 AM post.
*April 24, 2014*

**math**

P1 = Po(1+r)^n Po = $5,000 r = (6%/2)/100% = 0.03 = Semi-annual % rate expressed as a decimal. n = 2comp./yr * 2yrs. = 4 Compounding periods. P1 = 5000(1+0.03)^4 = $5627.54 after 2 years. P2 = P1(1+r)^n r = (8%/4)/100% = 0.02 = Quarterly % rate expressed as a decimal. n = ...
*April 24, 2014*

**math(compunded interest )**

a. P = Po(1+r)^n Po = $19,999 r = (4.5%/6)/100% = 0.0075 n = 6comp./yr. * 2yrs. = 12 Compounding periods. Solve for P. b. P = Po(1+r)^n Po = $120,000 r = (5.75%/12/100% = 0.00479 = Monthly % rate expressed as a decimal. n = 12comp./yr. * 3.25yrs. = 39 Compounding periods. ...
*April 24, 2014*

**physics**

Re = 6*(6+6)/(6+6+6) = 6*12/18 = 72/18 = 4 Ohms.
*April 23, 2014*

**geometry**

h = Vm^3/pi*(dm/2)^2 = Vm^3/pi*dm^2/4 = Vm^3 * 4/pi*dm^2 = 4Vm/pi*d = 4Vm/3.14d = 1.27Vm/d = 1.27V/d Meters.
*April 23, 2014*

**Physcs**

Vp = 300km[135o]/0.75h = 400 km/h[135o] Without the wind. Vp + Vw = 400km/h[135] = -282.84+282.84i Vp - 80i = -282.84 + 282.84i Vp = -282.84 + 282.84i + 80i Vp = -282.84 + 362.8i=460.4km/h[128o] = 460.4km/h[38o] W. of N. With the wind blowing.
*April 23, 2014*

**physics**

Fb = m*g = 225kg * 9.8N/kg = 2205 N. = Force of box. = Normal force. Fk = u*Fn = 0.20 * 2205 = 441 N. = Force of kinetic friction. a=(Fap-Fk)/m = (2205-441)/225=7.84 m/s^2
*April 23, 2014*

**Physics**

FRICTION is the force that opposes motion.
*April 23, 2014*

**physics**

F1 + F2 + F3 = 0 1800N[75o] + 1800N[294o] + F3 = 0 1800*cos75+i1800*sin75 + 1800*cos294+i 1800*sin294+F3 = 0, 465.87+i1738.7 + 732.1+i(-1644)+F3 = 0 1198 + i94.7+F3 = 0 F3 = -1198 - i94.7 = -1202 N.[4.52o] Tan Ar = -94.7/-1198 = 0.07905 Ar = 4.52o = Reference angle. A = 4.52...
*April 23, 2014*

**finance**

P = Po(1+r)^n Po = $11,000 r = (3%/4)/100% = 0.0075 = Quarterly % rate expressed as a decimal. n = 4comp./yr. * 9yrs. = 36 Compounding periods. Plug the above values into the given Eq and solve for P(principal).
*April 23, 2014*

**math**

P = Po(1+r)^n Po = $7700 Compounded Quarterly? r = (6%/4)/100% = 0.015 = Quarterly % rate expressed as a decimal. n = 4 comp./yr. * 5yrs = 20 Compounding periods. Plug the above values into the given Eq and get P = $10,370.78. I = P-Po
*April 22, 2014*

**physics**

V^2 = Vo^2 + 2g*h = 0 + 19.6*2 = 39.2 V = 6.26 m/s.
*April 22, 2014*

**Physic**

a. Impulse = 0.135*(36+47) = 11.2 b. a = (V2-V1)/t a = (47-(-36))/7*10^-4 = 118,571 m/s^2. F = m*a = 0.135 * 118,571 = 16,007 N.
*April 22, 2014*

**Physics**

See previous post: Mon,4-21-14,2:27 PM.
*April 22, 2014*

**Physics**

d1 = d2 0.5a*t^2 = 25t 0.5a*t = 25 0.5*0.004t = 25 t = 12,500 s. = 3.5 h.
*April 22, 2014*

**Physics**

See previous post: Mon,4-21-14,2:27 PM.
*April 22, 2014*

**physics**

h = 0.5g*t^2 = 10,000 Ft. 16t^2 = 10,000 t^2 = 625 Tf = 25 s. = Fall time. V*Tf = 2.09 miles. V * 25s = 2.09 V = 0.0836 mi/s * 3600s/h = 301 mi/h.
*April 22, 2014*

**Inverse Trig**

Y = arcsin1 = The angle whose sine is 1= 90o.
*April 21, 2014*

**Physics**

V=d/t = 300/0.75=400 km/h[135o]. Without wind. V = 400[135] + 80[270o] X == 400*cos135 = -282.8 km/h. Y = 400*sin135 + 80*sin270 = 202.8 km/h. Tan Ar = Y/X = 202.8/-282.8 = -0.71727 Ar = -35.65o = Reference angle. A = -35.65 + 180 = 144.3o V = X/cosA = -282.8/cos144.3 = 348 km...
*April 21, 2014*

**Physics**

Vp + Vw = 200kn/h[90o] Vp + (-50) = 200i Vp = 50 + 200i = 206.2km/h[76o]
*April 21, 2014*

**Physics**

Vo = 6.2m/s[10o] Xo = 6.2*cos10 = 6.106 m/s. Yo = 6.2*sin10 = 1.077 m/s. 1. h = ho + (Y^2-Yo^2)/2g h = 11 + (0-(1.077)^2)/-19.6 = 11.06 m. Above gnd. 2. h = 0.5g*t^2 = 11.06 m. 4.9t^2 = 11.06 t^2 = 2.257 t = 1.50 s. 3. d = Xo * t = 6.106m/s * 1.50s=9.17 m. 4. Y^2=Yo^2 + 2g*h= ...
*April 21, 2014*

**physics**

What is the air temperature?
*April 21, 2014*

**physics**

What is the temperature of the air?
*April 21, 2014*

**physics**

db1 = 10*Log(I/Io) db1 = 10*Log(10^(-11)/10^(-12) = 10*Log(10^(-11)*10^12) = 10*Log(10) = 10*1 = 10. db2 = 10*Log(10^(-8)/10^(-12) = 10*Log(10^(-8)*10^12) = 10*Log(10^4) = 10 * 4 = 40. 40 - 10 = 30db Difference.
*April 21, 2014*

**physics**

F = (9/5)C + 32 = 46o 1.8C = 46-32 = 14 C = 7.78o V=0.6T + 331 = 0.6*7.78 + 331=335.7 m/s. L = V*(1/F) = V/F = 335.7/1640=0.2047 m.
*April 21, 2014*

**Physics**

F = 120N.[130o] Fx = 120*cos130 = -77.13 N. Fy = 120*sin130 = 91.93 N.
*April 20, 2014*

**physics**

Mass = 1800Lb * 0.454kg/Lb = 817.2 kg V=30mi/h * 1600m/mi * 1h/3600s=13.33 m/s KE=0.5m*V^2 = 0.5*817.2*13.33^2 = 72,604 Joules. KE = 0.5m*(2V^2) = .5m*4V^2 = 4 times as great. KE = 0.5*0.002*500^2 = 250 J.
*April 17, 2014*

**personal finances**

B. is my choice.
*April 17, 2014*

**trig**

Mass = 725Lbs * 0.454kg/Lb = 329.2 kg. m*g = 329.2 * 9.8 = 3226 N. = Wt. of trailer. Fp = 3226*sin36 = 1896 N. = Force parallel to the ramp. F = Fp = 1896 N. Required.
*April 16, 2014*

**math**

A. I = Po^r*t = 1629.53*(0.1950/365)*21 = $18.28 B. Same procedure as A.
*April 16, 2014*

**math**

P = Po(1+r)^n Po = $1000. r = (3%/12)/100% = 0.0025 = Monthly % rate expressed as a decimal. n = 10yrs. * 12Comp/yr = 120 Compounding periods. Plug the above values into the given Eq and solve for P. I = P - Po
*April 16, 2014*

**Physical sciences**

Vd=100,000m/1h * 100000m/3600s=27.8 m/s = Velocity of driver. Fd = ((Vs-Vd)/(Vs+Ve))*Fe Fd = ((343-27.8)/(343+0))*900Hz Fd = (315.2/343) * 900 = 827 Hz = Freq. heard by driver. Vs = Velocity of sound in air. Ve = Velocity of the sound emitter (siren). Fe = Freq. emitted.
*April 16, 2014*

**consumer math**

I = Po*r*t = $60. 472.46*r*1 = 60 r = 0.127 = 12.7% = APR 0.25 * 629.95 = $157.49 = Down payment. 629.95 - 157.49 = $472.46=Amt. financed. (472.46+60)/12 = 532.46/12 = $44.37/mo. 472.46 + 60 = $532.46 = Total paid.
*April 16, 2014*

**physics**

Do/Dw = 0.84 Do/1 = 0.84 Do = 0.84 g/cm^3 = Density of the object Do/Df = 0.74 0.84/Df = 0.74 0.74Df = 0.84 Df = 1.135 g/cm^3 = Density of the fluid.
*April 16, 2014*

**math**

(680cm^3/s) / (1767cm^2/s) = 0.3848 cm = 0.003848 m.
*April 15, 2014*

**Geometry**

Divide both sides of Eq1 by (-4): Eq1: +3x + 2y = 5 Eq2: -3x + 9y = -27 Sum: 11y = -22 Y = -2 In Eq1, replace Y with (-2) and solve for X: 3x + 2*(-2) = 5 3x - 4 = 5 3x = 9 X = 3 Solution set: (x,y) = (3,-2)
*April 15, 2014*

**physics**

Circumference=pi*2r = 3.14 * 4m=12.57 m. V = 1800rev/min * 12.57m/rev * 1min/60s= 377 m/s.
*April 15, 2014*

**math**

Tan(90-31) = Y1/31 Tan(59) = Y1/31 = 1.66428 Y1=31 * 1.66428 = 51.6 = Ht. of shorter tower. Y1+Y2 = 51.6 + 31*sin25 = 64.7 m. = Ht. of taller tower.
*April 13, 2014*

**physical science**

d = V*t = 800 m. V * 5/2 = 800 V = 320 m/s.
*April 13, 2014*

**science**

Momentum = m*V = 20 * 5 = 100 kg-m/s.
*April 13, 2014*

**Physics**

C(-1.5,0.5), P(x,y) r^2 = (x+1.5)^2 + (y-0.5)^2 = 3^2 x^2+3x+2.25 + y^2-y+0.25 = 9 x^2+3x + y^2-y = 9-2.25-0.25 = 6.5 x^2+3x=(3/2)^2 + y^2-y+(-1/2)^2 = 6.5 x^2+3x+9/4 + y^2-y+1/4 = 26/4+9/4+1/4 x^2+3x+9/4 + Y^2-y+1/4 = 36/4 Multiply both sides by 4: 4x^2+12x+9 + 4y^2-4y+1 = 36...
*April 12, 2014*

**algebra**

Isn't there a sign between 30,000 and 1?
*April 12, 2014*

**maths**

KE = 0.5m*V^2 = 1000 J. 0.5*0.0081V^2 = 1000 0.00405V^2 = 1000 V^2 = 246,913 V = 497 m/s.
*April 12, 2014*

**Physics**

Vo = 210m/s[70o] Xo = 210*cos70 = 71.82 m/s. Yo = 210*sin70 = 197.3 m/s. 1. h = (Y^2-Yo^2)/2g=(0-197.3^2)/-19.6 = 1986 m.
*April 11, 2014*

**physics**

d = 0.5a*t^2 = 6 m. 0.5a*3.3^2 = 6 5.445a = 6 a = 1.102 m/s^2. V^2 = Vo^2 + 2a*d = 0 + 2.204*6 = 13.22 V = 3.64 m/s.
*April 10, 2014*

**math**

L = ? W = 8 h = 4 2W*h + 2L*h = 256 mm^2 2(8*4) + 2(L*4) = 256 64 + 8L = 256 8L = 256-64 = 192 L = 24 mm. Vol. = L*W*h = 24 * 8 * 4 = 768 mm^3
*April 10, 2014*

**Math**

P = 6 + 6*0.019*42 = 10.8 Billion.
*April 10, 2014*

**Algebra**

sqrt(-70)^2 = sqrt(70*(-1))^2 = 70*i^2 = 70 * (-1) = -70
*April 9, 2014*

**physics**

V=110km/h = 110,000m/3600s = 30.56 m/s. a=(V-Vo)/t = (30.56-0)/0.005=6111 m/s^2. F = m*a = 0.35 * 6111 = 2139 N.
*April 9, 2014*

**physics**

a = (V-Vo)/t = (30-0)/4 = 7.5 m/s^2.
*April 9, 2014*

**physics**

d = 53 + 53/5 = 63.6 m. T = d/r = 63.6/5 = 12.72 s.
*April 9, 2014*

**physics**

Fs = m*g = 127kg * 9.8N/kg = 1245 N. = Wt. of skier and toboggan. sin A = Y/r = 1.65/2.53 = 0.6522 A = 40.7o Fk = u*mg-u*T*sinA Fk = 1245u - u*148*sin40.7 Fk = 1245u - 96.5u = 1148u 148*cos40.7 - 1148u = m*a = m*0 = 0 1148u = 112.2 u = 0.098
*April 9, 2014*

**Physical sciences**

Fc = m*g = 330kg * 9.8N/kg = 3234 N. = wt. of crate. Fp = 3234*sin30 = 1617 N. = Force parallel to the incline. Fe - Fp = m*a Fe - Fp = m*0 = 0 Fe = Fp = 1617 N. = Force exerted.
*April 9, 2014*

**physics**

Circumference=pi*2r = 3.14 * 0.53=1.665 m. Va = 33.4m/s * 6.28rad/1.665m=126 rad/s a=(V-Vo)/t = (126-0)/11.6=10.87 rad/s^2.
*April 9, 2014*

**Physics**

Correction: Fk = u*Fc-u*Fap*sin27.3 Fk = 0.442*218.54 - 0.442*Fap*sin27.3 Fk = 96.6 - 0.203Fap Fap*cos27.3-(96.6-0.203Fap) = m*a 0.889Fap - 96.6 + 0.203Fap = m*0 1.092Fap = 96.6 Fap = 88.5 N. = Force applied. W = Fap*cos27.3 * d W = 88.5*cos27.3 * 9.3 = 731.3 J.
*April 8, 2014*

**Physics**

Fc = m*g = 22.3kg * 9.8N/kg = 218.54 N = Wt. of cart. Fk = u*Fc = 0.442 * 218.54 = 96.6 N. = Force of kinetic friction. Fap*cos27.3-Fk = m*a Fap*cos27.3-96.6 = m*0 = 0 Fap*cos27.3 = 96.6 N. W=Fap*cos27.3 * d = 96.6 * 9.3=898.3 J. Fap = Force applied = Tension in rope.
*April 8, 2014*

**Math**

X Tickets @ $75 each. (3500-X) Tickets @ $110 each. 75x + 110(3500-x) = 245,000+0.25*245,000 75x + 385,000-110x = 306,250 -35x = 306,250-385,000 = -78,750 X = 2250 Seats @ $75 each. 3500-x=3500-2250 = 1250 seats @ @110each
*April 8, 2014*

**math**

9x^2 * x^3 = 32 x^5 = 32 x^5 = 2^5 x = 2
*April 8, 2014*

**Physict**

d = d1(V2/V1)^2 = 15(150/50)^2 = 135 m.
*April 8, 2014*

**math**

0.05 * 173,000,000
*April 7, 2014*

**math word problem**

See previous post: Mon, 4-7-14, 3:36 PM.
*April 7, 2014*

**math**

See previous post.
*April 7, 2014*

**geometry**

2. m AB = (5-2)/(2-0) = 3/2. m BC = (0-5)/(3-2) = -5/1 = -5. 3. A'(-4,4), B'(-2,7), C'(1,2). 4. m AB' = (7-4)/(-2+4) = 3/2. m BC' = (2-7)/(1+2) = -5/3
*April 7, 2014*

**Math word problems**

L = 15x + 15y L = 15(x + y) x = 5 3/8 Yards y = 3/4 Yard L = Total length x + y = 5 3/8 + 3/4 = 43/8 + 6/8 = 49/8 = 6 1/8 Yards. L=15 * 49/8 = 91.875 Yards = 91 7/8 Yds.
*April 7, 2014*

**physics**

KE = m*V^2/2 = 4 * 4^2/2 = 32 Joules.
*April 7, 2014*

**Math**

See previous post: Sat, 4-5-14, 10:04 PM.
*April 6, 2014*

**physics**

Freq. = 5*10^6rad/s * 1rev/6.28rad = 7.958*10^5 rev/s = 7.958*10^5 Hz. Xl = WL = (6.28*7.958*10^5)*100*10^-6 = 500 Ohms. Xc=1/WC = 1/(6.28*7.958*10^5)*100*10^-12 = 2000 Ohms. Z = R + j(Xl-Xc) = 30 + j(500-2000) = 30 - j1500 = 1500.3Ohms [-88.9o] I = V/Z = 1.0[0o]/1500.3[-88.9...
*April 6, 2014*

**Math**

P(t) = 100(1-e^-0.12*3) P(3) = 100(1-0.6977) = 30.23% Fails. 100% - 30.23% = 69.7% Usable.
*April 5, 2014*

**Math**

The largest exponent of the variable is 2. Therefore, it is a 2nd degree polynomial.
*April 5, 2014*

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