Thursday

August 21, 2014

August 21, 2014

Total # Posts: 8,916

**Physics Please check my answers**

1. Circumference=Pi*D=3.14 * 16=50.27 m. V = 15rev/60s * 50.27m/rev = 12.56 m/s. 2. 0.5*5*t^2 = 20*t 2.5t^2 - 20t = 0 t = 8 s. (Use Quad. Formula). d = 20 * 8 = 160 m. 3. d = Yo*t + 4.9*t^2 d = -10*2.5 + 4.9*2.5^2 = 4. 1. 5. Work = !0*F*d = 10*(mg)*d Work = 10*(1960)*1 = 19,...
*January 17, 2014*

**algebra**

Y = (1/4)x + 2 Y = (1/4)x m1 = m2 = 1/4 The lines are parallel, because their slopes are equal.
*January 17, 2014*

**Earth Science**

Mass of silver=5cm^3 * 10.5g/cm^3=52.5g. Mass of gold=5cm^3 * 19.3g/cm^3 = 96.5g.
*January 17, 2014*

**physics**

Work = F*d = 335 * 2.07 = 693.5 J.
*January 17, 2014*

**Physics**

Vs = 0.3kg * 1m^3/100kg = 0.003 m^3 = Vol. of Styrofoam = Vol. of water Dis- placed. Mass = 0.003m^3 * 100kg/m^3 = 0.3 kg. T = 0.3kg * 9.8N/kg = 2.94 N. Note: Density of water = 1000kg/m^3.
*January 17, 2014*

**Finance**

Rate = $X per hour. Pay = 28X + 253 = 400 28x = 400 - 253 = 147 X = $5.25 per hour.
*January 17, 2014*

**QUANTITATIVE REASONING FOR BUSINESS**

D = P-T
*January 17, 2014*

**math**

Equivalent fraction = 6/8. (6/8)/(1/8) = 6/8 * 8/1 = 6 Strips.
*January 16, 2014*

**Physics**

h = ho + (V^2-Vo^2)/2g h = 1.75 + (0-19^2)/19.6 = 20.17 m. Xo = 8 m/s = Hor. component of initial velocity. Yo = Ver. component of initial velocity. Vo = 19 m/s = Total initial velocity. cos A = Xo/Vo = 8/19 = 0.42105 A = 65.1o = Angle at which rock is thrown. Yo = Vo*sin A = ...
*January 16, 2014*

**Geometry - 8th grade**

Total Degrees = (N-2)*180 = (5-2)180=540 Missing Angle = 540-(85+110+135+95)=115o
*January 16, 2014*

**Math**

X Heads to start with. (X-24) = Bal. (X-24) - 2/7(X-24) = 5/7(x-24). 5/7(X-24) = X/2 Multiply both sides by 14: 10x-240 = 7x 3x = 240 X = 80 Heads of lettuce.
*January 16, 2014*

**PHYSICS**

Assuming no friction: KE = PE = mg*h = (5*9.8)*10=490 Joules.
*January 16, 2014*

**Algebra**

d1 = (Vb-4)t = 20 Eq1: Vb*t - 4t = 20 d2 = (Vb+4)t = 60 Eq2: Vb*t + 4t = 60 Multiply Eq1 by -1: -Vb*t + 4t = -20 +Vb*t + 4t = 60 Sum:0 + 8t = 40 t = 5 h. In Eq1, replace t with 5: Vb*5 - 4*5 = 20 5Vb = 40 Vb = 8 mi/h = Velocity of the boat.
*January 15, 2014*

**Physics**

d = Xo*T = 68 m. Xo * 2.276 = 68 Xo = 29.9 m/s. = Hor. component of initial velocity. Vo = Xo/cosA = 29.9/cos20.5 = 31.9 m/s = Initial velocity. Impulse = m*Vo = 0.27 * 31.9 = 8.61 kg.m/s.
*January 15, 2014*

**physics**

PE = mg*h = 17*9.8*3.5 = 583.1 Joules. KEo = 583.1 J. , No friction. KE = 0.5m*V^2 = 8.5*4.5^2 = 172.1 J., With friction. KE Lost = KEo-KE = 583.1-172.1 = 411 J. = Work done by friction.
*January 15, 2014*

**pre cal**

a. C = 8.48x + 5.69 b. (X,C),(0,5.69),(50,429.69),Add more points for graphing. c. C = 8.48*200 + 5.69 = $1701.69 d. Same procedure as c. e. Slope = 8.48
*January 15, 2014*

**math**

Tia collected $10 for a walkathon and $ 5 from each friend. What is the total amount of donations she collected from 4 friends? Is my answer below correct? Friend - 1,2,3,4 Donations - $5, $5, $5, $5 = $20 Answer is $20 from 4 friends.
*January 14, 2014*

**physics**

V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d a = (46.5^2-0)/89.6 = 24.13 m/s^2 F = m*a = 57 * 24.13 = 1376 N.
*January 14, 2014*

**physics**

What do you want to know?
*January 14, 2014*

**Pre-Calc**

b. d = 80t - 16t^2 = 96 -16t^2 + 80t - 96 = 0 Divide both sides by 16: -t^2 + 5t - 6 = 0 Use Quadratic Formula and get: t = 2s, and 3 s. Interval: 2< T <3. c. h = (V^2-Vo^2)/2g h = (0-80^2)/64 = 100 Ft. d. V = Vo + g*t = 0 at max ht. t = -Vo/g = -80/-32 = 2.50 s.
*January 14, 2014*

**math**

Tia collected $10 for a walkathon and $ 5 from each friend. What is the total amount of donations she collected from 4 friends? Is my answer below correct? Friend - 1,2,3,4 Donations - $5, $5, $5, $5 = $20 Answer is $20 from 4 friends.
*January 14, 2014*

**5th grade math**

C = 6P + 2 C = 6*5 + 2 = $32.
*January 14, 2014*

**Physics**

F1 = 10N[0o]. F2 = 10N[45o]. F3 = 10N[90o]. F4 = 10N[270o]. F5 = 10N[315o]. X = 10*cos0+10cos45+10cos90+10cos270+10 cos315=10 + 7.07 + 0 + 0 + 7.07=24.14 N. Y = 10sin0+10sin45+10sin90+10sin270+10 sin270+10sin315 = 0 + 7.07 + 10 - 10 - 7.07 = 0 N. F = X + Yi = 24.14 + 0 = 24.14...
*January 14, 2014*

**math 7**

Correction: Ricky's age 10 yrs from now =(2x-3)+10 = 2x+7.
*January 13, 2014*

**math 7**

Nila's age = X yrs old, now. Nila's age = (X-3) yrs old, 3 yrs ago. Ricky's age = 2(X-3) yrs old, 3 yrs ago. Ricky-Nila = 2(X-3)-(X-3) = (X-3) yrs older than Nila. Ricky's age, now = X + (X-3) = (2x-3) yrs old. Ricky's age 10 yrs from now = 10(2x-3) = (20x-...
*January 13, 2014*

**Physics**

Vo = 68km/h = 68,000m/3600s = 18.89 m/s. V=Vo + a*t = 18.89 + 1.35*4.7 = 25.2m/s = Final velocity. D = Vo*t + 0.5*a*t^2 D = 18.89*4.7 + 0.5*1.35*4.7^2=103.7 m.
*January 12, 2014*

**physics**

d^2 = (2n)^2 + n^2 = 112^2 4n^2 + n^2 = 12,544 5n^2 = 12544 n^2 = 2508.8 n = 50 m. = North leg. 2n = 100 m. = West leg. tan A = 2n/n = 2.0 A = 63.43o West of North = Direction.
*January 12, 2014*

**Physics**

a=(V-Vo)/t = (15-75)/12.55 = -4.78 m/s^2 d = Vo*t + 0.5*a*t^2 d = 75*12.55 + 0.5*(-4.78)*12.55^2 = 564.8 m.
*January 12, 2014*

**Physics**

D = -20 + 13 - 30i - 27 = -34 - 30i tan Ar = -30/-34 = 0.88235 Ar = 41.42o = Reference angle. A = 41.42 + 180 = 221.4o D = -34/cos221.4 = 45.3km[221.4o].
*January 12, 2014*

**physics**

V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*7.34 = 143.864 V = 12 m/s.
*January 12, 2014*

**business math**

P = Po*(1+r)^n r = 11%/100% = 0.11 = APR expressed as a decimal. n = 1Comp/yr * 19yrs = 19 Compounding periods. Plug the above values into the given Eq
*January 12, 2014*

**business math**

1. P = Po*(1+r)^n r = (8%/4)/100% = 0.02 = Quarterly % rate expressed as a decimal. n = 4Comp /yr * 1yr = 4 Compounding periods. P = 1,000,000(1.02)^4 = 1,082,432.16 Int. = P-Po 2. APY = (I/Po)*100% =
*January 10, 2014*

**trig**

Both answers are correct.
*January 10, 2014*

**MATH**

1. I = P*r*t = 1200*0.04*3 = $144.00 2. $160/$100 = 1.60 = 160% % Mark-up = 160% - 100% = 60 %. 3. 70/50 = 1.40 = 140 %. %Increase = 140%-100% = 40 %. 4. 60/75 = 0.80 = 80 % %Decrease = 80% - 100 = -20%.
*January 10, 2014*

**Science**

a = F/m = 320/58.2 = 5.5 m/s^2.
*January 10, 2014*

**Math**

Reiny, we meet again!! LOL! Oh well, we got the same answer!
*January 10, 2014*

**Math**

Eq1: 3x - 9y = 3 Eq2: 6x - 3y = -24 In Eq1, solve for X: 3x = 9y + 3 X = 3y+1 In Eq2, replace X with 3y+1: 6(3y+1) - 3y = -24 18y+6 - 3y = -24 15y = -30 Y = -2. In Eq1, replace Y with-2: 3x-9*(-2) = 3 3x + 18 = 3 3x = -15 X = -5. Solution set: (-5,-2). Eq1: Y - X/2 = 6 Eq2: 2x...
*January 10, 2014*

**Inequalities help?**

1. m-7 < 6 m < 6+7 m < 13 2. p + 12 > 9 p > 9-12 p > -3 3. x - 5 => 9
*January 10, 2014*

**physical science**

V = 36m/s * 1mi/1600m * 3600s/h = 81mi/h
*January 9, 2014*

**Physics**

m1*V1-m2*V2 = 4.82*5.03-2.72*3.52=14.7 m*V = 14.7 V = 14.7/m = 14.7/(4.82+2.72) = 1.95 m/s
*January 9, 2014*

**Physics forces unit**

F = m*a If you know any 2 of the 3, you can calculate the third: m = F/a.
*January 9, 2014*

**Math**

X hrs in town. (1-X) hrs in country. 40x + 50(1-x) = 48 km 40x + 50-50x = 48 -10x = -2 X = 0.2 Hours in town 1-X = 1-0.2 = 0.8 hrs = 48 min. in the country.
*January 9, 2014*

**math**

d = (3/12) * 5.9*10^12 = 1.475*10^12 mi. You are correct.
*January 9, 2014*

**Math**

Total Cost = 10 + 32 = $42. CDs Bought = $42/$7 = 6.
*January 8, 2014*

**math**

2*1 + 48/10 + 5*100 = 2 + 4.8 + 500 = 506.8
*January 8, 2014*

**physics**

Impact = m1*V1-m2*V2=87*5-83*2.92=192.6 m*V = 192.6 V = 192.6/m = 192.6/(87+83) = 1.133 m/s
*January 8, 2014*

**physics**

See previous post.
*January 8, 2014*

**physics**

A. V = Vo + g*t = 0 500 - 9.8t = 0 9.8t = 500 Tr = 51.02 s. = Rise time = Time to reach max ht. B. T = Tr+Tf Tf = Tr = 51.02 s. = Fall time. T = 51.02 + 51.02 = 102.04 s. to reach gnd.
*January 8, 2014*

**trig**

d = 50mi * 5280Ft/m1 = 264,000 Ft. = 264K. (0,10k), (264k,20k). Tan A = (20k-10k)/(264k-0) = 0.037879 A = 2.2 Degrees.
*January 8, 2014*

**physics**

h(t) = ho - 0.5g.t^2 h(2) = 600 - 4.9*2^2 = 580.4 m. Above gnd. V(2) = Vo + g*t = 0 + 9.8*2 = 19.6 m/s. h(5) = 600 - 4.9*5^2 = 477.5 m. Above gnd. V(5) = 0 + 9.8*5 = 49 m/s. h(10) = 600 - 4.9*100 = 110 m. Above gnd. V(10) = 0 + 9.8*10 = 98 m/s.
*January 8, 2014*

**physics**

K = 30 + 273.15 = 303.15o Kelvin (2*10^-5/K)*303.15K*10cm = 0.06063 cm Increase in Length, each side. (0.06063)^3 = 2.2288*10^-4 cm^3 Increase in Volume.
*January 8, 2014*

**Physics**

Fg = m*g = 73 * 10 = 730 N. = Force of gravity. Fg-Fk = m*a 730-Fk = 73 * 5 = 365 N. -Fk = 365-730 = -365 Fk = 365 N. = Force of kinetic friction.
*January 7, 2014*

**physics**

Momentum = m1*V1 - m2*V2= 1*10-3*2=4 in the direction of m1. m*V = 4 V = 4/m = 4/(1+3) = 1 m/s. in the direction of m1.
*January 7, 2014*

**Math**

14. b. Debt = $25. 15. c. Debt < $25. 12. a. Debt > $25.
*January 7, 2014*

**physical Science**

Momentum = m*V = 200kg * 1m/s = 200. Momentum = m*V = 1kg * 200m/s = 200.
*January 7, 2014*

**physics**

240N/2cm^2 = 120N/cm^2
*January 6, 2014*

**physics**

240N/2cm^2 = 120N/cm^2 240N/40cm^2 = 6N/cm^2
*January 6, 2014*

**physics**

240N/2cm^2 = 120N/cm^2
*January 5, 2014*

**physics**

240N/40cm^2 = 6N/cm^2
*January 5, 2014*

**physics**

d = (150/50) * 15m = 135.
*January 5, 2014*

**physics**

d = d = (150/50)^2 * 15m = 135 m.
*January 5, 2014*

**math**

If L is known: 1. Plug-in the value of L. 2. Simplify the quantity under the radical. 3. Take the square root of the number under the radical. Example: L = 19.6 m. Solve for T. T = 2pi*sqrt((2/3)*L/g) T = 6.28*sqrt((2/3)*19.6/9.8) = 6.28*sqrt((2/3)*2) = 6.28*sqrt((4/3) = 6.28...
*January 1, 2014*

**Physics**

Does your textbook give the mass of the sled?
*January 1, 2014*

**Physics**

d = Vo*t + 0.5a*t^2 = 6 m. 0 + 0.5a*4^2 = 6 8a = 6 a = 0.75 m/s^2. Fp = m*g = 25kg * 9.8N/kg = 245 N. = Force of pickle. Fap-Fp-Fk = m*a Fap-245-3.8 = 25*0.75 Fap = 18.75+245+3.8 = 267.6 N. = Force applied. Work = Fap * d = 267.6 * 6 = 1605 Joules
*January 1, 2014*

**Math**

Correction: (30-X) Hrs. @ $12 per Hr. NOT (30-8).
*December 31, 2013*

**Math**

X Hrs @ $8 per hr. (30-8) Hrs @ $12 per hr. 8x + 12(30-x) = $268 8x + 360 - 12x = 268 -4x = 268-360 = -92 X = 23 Hrs. @ $8 per hr. 30-23 = 7 Hrs @ $12 per hr.
*December 31, 2013*

**Maths**

Reiny, you finished ahead of me; but i'm glad we got the same answer!
*December 30, 2013*

**Maths**

Mary = X Stamps. Wendy = X + 80 Jean = (X+80)-50 = X + 30 After Transactions: Mary= X + (X+80)/2 = (3X/2+40). Mary = 4/5(3X/2+40) = 6X/5+32 Wendy = (X+80)/2 Jean = (X+30)+3X/10+8=13X/10+38 Jean = (13X/10+38)=(X/2+40)+62 13X/10-X/2 = 62+40-38 = 64 13X/10-5X/10 = 64 8X/10 = 64 ...
*December 30, 2013*

**science**

A. Difference.
*December 30, 2013*

**Trigonometry**

I assumed you mean one surface is 576 cm^2. We have 6 equal surfaces. As = 6 * 576cm^2 = 3456 cm^2.
*December 29, 2013*

**physics**

F = 0.1kg * 9.8N/kg = 0.98N/kg = 0.98 N. K = F/d = 0.98N/0.04m = 24.5N/m.
*December 27, 2013*

**Physics**

Mass=540*10^3m^3 * 4.3*10^-3kg/m^3 = 2322 kg. Fb = m*g = 2322kg * 9.8N/kg = 22,756 N.
*December 24, 2013*

**physics**

V(co2) = (4500g/0.8g) * 1cm^3=5625 cm^3 V(co2)/Vex = 5625/7.1*10^3 = 0.79 = 79%.
*December 23, 2013*

**Environmental Science**

1.1kW = 1.1kJ/s T = 2.85*10^7kJ * 1s./1.1kJ * 1h/3600s * 1day/24h = 300 Days.
*December 22, 2013*

**physics**

Ws = m*g = 80kg * 9.8N/kg = 784 N. = Wt. of sled. Fp = 784*sin25 = 331.3 N. = Force parallel to the incline. Fn = 784*cos25 = 710.5 N. = Normal force = Force perpendicular to the incline. Fk = u*Fn = 0.7 * 710.5 = 497.4 N. = Force of kinetic friction. F-Fp-Fk = m*a F-331.3-497...
*December 21, 2013*

**math**

Rate = 300/6 = 50 Words/min. 2. $4.00/25 oz = $016/oz. $7.00/90oz = $0.08/0z. 3. d/12 = 96/8 8d = 12*96 = 1152 d = 1152/8 = $144
*December 21, 2013*

**physics**

Elastic limit.
*December 19, 2013*

**Science**

Yes, I use that trick when there are more conversions than we have here.
*December 19, 2013*

**Science**

V = 32km/h = 32000m/3600s = 8.89 m/s. 32km = 32,000 m. 1h = 3600s.
*December 19, 2013*

**math**

See previous post: 8:51 AM.
*December 19, 2013*

**physics**

V^2 = Vo^2 + 2a*d a = (V^2-V0^2)/2d a = (51^2-0)/150 = 17.34 m/s^2.
*December 18, 2013*

**math help**

(1*2*3*z)^2 = 144 (6z)^2 = 144 36z^2 = 144 z^2 = 4 Z = +-2.
*December 18, 2013*

**Physics**

See 3:47 AM post.
*December 18, 2013*

**Physics**

h = 50 m. Vo = 35m/s[50o] Xo = 35*cos50 = 22.50 m/s. Yo = 35*sin50 = 26.81 m/s. a. Y = Yo + g*t = 0 at max ht. 26.81 - 9.8t = 0 9.8t = 26.81 Tr = 26.81/9.8 = 2.74 s. = Rise time. hmax=ho + Yo*Tr - 0.5g*Tr^2 hmax=50+26.81*2.74 - 4.9*2.74^2=86.67 m. Above gnd. 0.5g*t^2 = 86.67 4...
*December 18, 2013*

**Physics**

1D. Cannot be determined, because we don't know the time. 2D. 5D.V = a*t = 2m/s^2 * 8s. = 16 m/s. 6B. V = Vo + g*t = 0 + 10*4 = 40 m/s. 7A. X = 100*cos 30 = 87 N. 8B.
*December 17, 2013*

**Physics**

F = (0.06m/1m) * 18N = 1.08 N. a = F/m = 1.08/7.66*10^-3 = 141 m/s^2. V^2 = Vo^2 + 2a>d V^2 = 0 + 282*0.06 = 16.92 V = 4.11 m/s. V^2 = 4.11^2 + 282*0.03 = 25.35 V = 5.03 m/s.
*December 17, 2013*

**Math**

L = (30/6) * 10Ft = 50 Ft
*December 16, 2013*

**physics- multiple choice**

1. True 2. 98 N, down. 3. Fn = m*g - 1000 = 600kg * 9.8-1000 = 5880 - 1000 = 4880 N.
*December 16, 2013*

**physics. HELP**

See previous post: Mon,12-16-13,7:15 PM.
*December 16, 2013*

**physics. HELP**

See previous post: Mon,12-16-13,7:11 PM.
*December 16, 2013*

**physics. HELP**

See previous post: Mon,12-16-13,7:07 PM.
*December 16, 2013*

**physics**

D = Xo * 1.8 = 30 m. Xo = 30/1.8 = 16.67 m/s=Hor. component of initial velocity. Y = Yo + g*Tr = 0 at max Ht. Yo - 9.8*(1.8/2) = 0 Yo - 8.82 = 0 Yo = 8.82 m/s = Ver. component of initial velocity. a. Vo^2=Xo^2 + Yo^2=16.67^2 + 8.82^2 = 355.7 Vo = 18.9 m/s = Initial velocity. b...
*December 16, 2013*

**physics**

Vo = 6 m/s[35o] = Initial velocity. Xo = 6*cos35 = 4.91 m/s.=Hor. component of initial velocity. Yo = 6*sin35 = 3.44 m/s=Ver. component of initial velocity. a. Y = Yo + g*t = 0 3.44 - 9.8t = 0 9.8t = 3.44 Tr = 3.44/9.8 = 0.3512 s. = Rise time. Tf = Tr = 0.3512 m/s = Fall time...
*December 16, 2013*

**physics**

D = Xo*t = 8.90 m Xo * 1.1 = 8.9 Xo = 8.9/1.1 = 8.09 m/s = Hor. component of initial velocity. Vo = Xo/cos A = 8.09/cos30=9.34 m/s[30o] = Initial velocity or take-off speed.
*December 16, 2013*

**physics**

d = V*t = 170 40*t = 170 t = 4.25 s. d2 = 0.5g*t^2 d2 = 4.9 * 4.25^2 = 88.5 m. = Vertical drop.
*December 16, 2013*

**phyics**

h = 1.5 m? h = 0.5g*t^2 = 1.5 m. Solve for t.
*December 16, 2013*

**math**

If the absolute value of a number is 21, the number can be positive or negative 21: 3x+12 => +-21 3x => +-21-12 X = (+-21-12)/3 = 3 or -11.
*December 16, 2013*

**algebra**

6j-5 < 2(3j-4) 6j-5 < 6j-8 6j-6j < -8+5 0 < -3. False.
*December 16, 2013*

**physics**

Net Force = Fap - Fk = 420-0.22*1420 = 107.6 N.
*December 16, 2013*

**physics**

d1 = 15m/s * 2s. = 30 m head start. d2 = 0.5a*t^2 = 30 + 15t 1*t^2 = 30 + 15t t^2 - 15t = 30 t^2 - 15t - 30 = 0 Use Quadratic Formula and get: t = 16.79 s.
*December 16, 2013*

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