Tuesday

September 2, 2014

September 2, 2014

Total # Posts: 8,975

**Physics**

L = V/F = 489*10^-9 m. 3*10^8/4.89*10^-7 = 6.13*10^14 Hz.
*January 26, 2014*

**physics**

Fr = (Vs-Vc)/(Vs+Va)*Fa Fc = (343-32.3)/(343+60.7)*521 = 401 Hz= Freq. heard by car driver.
*January 26, 2014*

**MATH**

In a school library, there are 3 Chinese Language books for every 5 English Language books. The number of Malay Language book is 5/9 as many as the Chinese Language books. Find the ratio of the number of Malay Language books to the number of English Language books. (Express ...
*January 26, 2014*

**physics**

You are a Middle Ages cannonball scientist attacking a castle a distance D away. Your job is to get a cannonball of mass m over the walls, which are a height H above the top of the cannonball launcher. At the instant when the cannonball leaves the launcher it will be traveling...
*January 26, 2014*

**physics**

While working on your physics homework in your dorm room you notice a flowerpot fall past your window because someone has carelessly knocked it off the roof. Fortunately, you computer¡¯s video camera captured the whole thing so you can measure the total time the pot...
*January 26, 2014*

**physical acience**

D = 360g/74cm^3 = 4.86 g/cm^3.
*January 26, 2014*

**Science**

See 9:59 AM post.
*January 26, 2014*

**Physics**

Xo = 50 m/s. = Hor. component. Y = 42 m/s = Ver. component. Tot. velocity = sqrt(50^2+42^2)=65.3 m/s
*January 26, 2014*

**Physics**

0.5g*t^2 = 90 m. 4.9t^2 = 90 t^2 = 18.37 t = 4.29 s. Distance = Xo*t = 50m/s * 4.29s=214.3 m. V = Vo+g*t = 0 + 9.8*4.29 = 42 m/s.
*January 26, 2014*

**physics**

Correction: F1 = -100i F5 = -100i-54.5i-88.3 = -88.3-154.5i Tan Ar = -154.5/-88.3 = 1.74972 Ar = 60.3o = Reference angle. A = 60.3 + 180 = 240.3o F5 = X/cos A = -88.3/cos240.3 = 178.2 N. [240.3o]
*January 26, 2014*

**physics**

Resultant = F1 = 100N[270o]. F2 = 250N[320o]. F3 = 100N[60o]. F4 = 200N[140o]. F5 = ? Add to get F1. X=250*cos320+100*cos60+200*cos140=88.3N Y=250*sin320+100*sin60+200*sin140=54.5N tan A = Y/X = 54.5/88.3 = 0.61680 A = 31.7o F2+F3+F4=X/cos A = 88.3/cos 31.7 = 103.8N[31.7o] = ...
*January 26, 2014*

**physics**

Tan29.3 = (47-15.1)/(17.4+d2) (17.4+d2)*Tan29.3 = 47-15.1 = 31.9 (17.4+d2) = (47-15.1)/Tan29.3 = 56.9 d2 = 56.9-17.4 = 39.5 Ft.
*January 25, 2014*

**college physics**

V = 80km/h = 80000m/3600s = 22.22 m/s. a. V = Vo + a*t = 22.22 m/s. 0 + 1.25t = 22.22. Solve for t. b. V = Vo + a*t = 0 22.22 - 1.75*t = 0. Solve for t. c. V = Vo + a*t = 0 22.22 + a*8.30 = 0. Solve for a; it should be negative.
*January 25, 2014*

**college physics**

a. V = Vo * a*t = 10 + 0.6*7 = 14.2 m/s. b. T = d/r1 - d/r2 = 300/10-300/14.2 = 8.87 s. Saved.
*January 25, 2014*

**physics**

L = Lo + a*(T-To)Lo L = 1.4 + 1.95*10^-5(32-(-15))1.4 = 1.401283 m.
*January 24, 2014*

**physics**

c^2 = a^2 + b^2 = 3.8^2 + 8.1^2 =
*January 24, 2014*

**science**

a=(V-Vo)/t = (12.4-0)/3.77 = 3.29 m/s^2 d = 0.5*3.29*3.77^2 = 23.37 m. Work = F*d = (m*g) * d=(1920*9.8)23.37 = 439,805 Joules.
*January 24, 2014*

**Math Interest Question**

AMT = 1.095 * $8,532 =
*January 24, 2014*

**Physics**

m*g = 8.35 N. 1.25 * g = 8.35 g = 6.68 m/s^2.
*January 23, 2014*

**physics**

V^2 = Vo^2 + 2g*d. Solve for V.
*January 23, 2014*

**Physics**

A. a=(V-Vo)/t = (0-30)/0.005=-6000 m/s^2 B. F = m*a = 0.145 * (-6000) = -870 N.
*January 23, 2014*

**Physics**

See previous post.
*January 23, 2014*

**Physics**

a. h = Vo*t + 0.5g*t^2 = 9 18t - 4.9t^2 = 9 -4.9t^2 + 18t - 9 = 0 t=0.597 s. and 3.08 s(Use quad. formula) Choose t = 0.597 s since the apple reaches its max ht. of 16.5 m, in 1.84 s. V = Vo + g*t = 0 @ max ht. 18 - 9.8*t = 0 9.8t = 18 Tr = 1.84 s. = Rise time. b. If student A...
*January 23, 2014*

**physics**

a. V = Vo + a*t = 0 24.5 - 2*t = 0 2t = 24.5 t = 12.25 s. b. d = Vo*t + 0.5a*t^2 d = 24.5*12.25 -0.5*2*12.25^2 = 150 m. c. d = 41.6 + 150 = 191.6 m. = Required stopping distance. V^2 = Vo^2 + 2a*d a=(V^2-Vo^2)/2d=(0-29.6^2)/383.2 = -2.29 m/s^2. d. V = Vo + a*t = 0 @ stopping ...
*January 23, 2014*

**Physics**

d = Vo*t + (V^2-Vo^2)/2a d = 20*0.8 + (0-20^2)/-14 = 44.6 m.
*January 22, 2014*

**Physics**

a = (V-Vo)/t = 5-0)/4.5 = 1.11 m/s^2. d1 = 0.5a*t^2 = 0.5*1.11*4.5^2=11.25 m. d2 = 5m/s * 4.5s = 22.5 m. D = d1 + d2 = 11.25 + 22.5 = 33.75 m.
*January 22, 2014*

**Algebra 1**

X = Total students. Eq: x/8 = 2 X = 16 Students.
*January 22, 2014*

**geometry**

A(0.0),B(0,2k),C(2h,0),P(h,k). (AP)^2 = (h-0)^2 + (k-0)^2 = h^2 + k^2 Ap = sqrt(h^2+k^2). (BP)^2=(h-0)^2 + (k-2k)^2=h^2 + (-k^2) BP = sqrt(h^2+(-k)^2). (CP)^2=(h-2h)^2 + (k-0)^2=(-h)^2 + k^2 CP = sqrt((-h)^2+k^2).
*January 22, 2014*

**Math**

P1-P2 = 5x+3 (-3x^2+4x+1) - P2 = 5x+3 P2 = (-3x^2+4x+1)-(5x+3) = -3x^2-x-2 = Polynomial # 2.
*January 22, 2014*

**physics**

Distance = 54m/lap * 77laps = 4158 m. Displacement = Df-Do = 0-0 = 0. Do = Starting point. Df = Final distance from starting point. V = D/t = 0/1.5 = 0 r = d/t = 4158/1.5 = 2772 m/h.=1.73 mi/h
*January 21, 2014*

**Physics**

F. V3 = 4 + 3 = 7. To add them directly, both must be on the X-axis.
*January 21, 2014*

**math**

Similar figures have the same shape but the size is usually different.
*January 21, 2014*

**Math**

An Eq is a mathematical statement that says two quantities are equal. The inequality says they are unequal(> or<).
*January 21, 2014*

**math**

Given: AC = 2x-5.3 Ft.
*January 21, 2014*

**math**

Given: AC = 2x-5.3 Ft.
*January 21, 2014*

**algebra 1**

7X-2y=-39 X+5y=5
*January 21, 2014*

**Algebra**

The Present: Son: X yrs old. Father: 7X yrs old. A year ago: Son: (x-1) yrs old. Father: 9(X-1) yrs old. The difference between their ages is the same as last year: 7x-x = 9(x-1)-(x-1) 6x = 9x-9-x+1 -2x = -8 X = 4 yrs = The son's age.
*January 21, 2014*

**physics**

d = 350 100 = 250 m. = Braking distance. a=(V^2-Vo^3)/2d=(0-60^2)/500=-7.2 m/s^2
*January 21, 2014*

**physics**

Vw=(10kg-4kg) * 1m^3/1000kg = 0.006 m^3 = Vol. of water displaced = Vol. of the object submerged. Do = 6kg/0.006m^3 = 1000kg/m^3 = Density of the object. = Density of water(Dw). Do/Dw * Vo = 0.006 m^3 (1000/1000) * Vo = 0.006m^3 Vo = 0.006 m^3 = Vol. of the object. So the ...
*January 21, 2014*

**physics**

What is the mass of the object?
*January 21, 2014*

**physics**

Vo = 85m/s[15o] Xo = 85*cos15 = 82.1 m/s. Yo = 85*sin15 = 22 m/s. Y = Yo + g8*Tr = 0 @ max ht. 22 - 9.8Tr = 0 9.8Tr = 22 Tr = 2.24 s. = Rise time. 0.5g*Tf^2 = h max = 37.7 m. 4.9Tf^2 = 37.7 Tf^2 = 7.69 Tf = 2.77 s. = Fall time. T = Tr + Tf = 2.24 + 2.77 = 5 s. = Flight time. h...
*January 20, 2014*

**physic**

T = 330/100 = 3.30 s. = The Period. T^2 = 4*pi^2(L/g) = 3.3^2 = 10.89 39.5(1.2/g) = 10.89 47.4/g = 10.89 10.89g = 47.4 g = 4.35 m/s^2
*January 20, 2014*

**physic**

Freq. = 1000rev/0.0876s = 11,416rev/s = 11,416 cycles/s = 11,416 Hz.
*January 20, 2014*

**math**

15x^2 - 102x = 3 Divide both sides by 3: 5x^2 - 34x = 1 5x^2 - 34x - 1 = 0 X = 6.83, and -0.03(Used Quad. Formula)
*January 20, 2014*

**college math HELP!!!!!**

P = -x/25 + 190 = -2250/25 + 190 = $100. = Equilibrium price. Check: P = x/75 + 70 = 100 x/75 = 30 X = 2250 Units.
*January 20, 2014*

**Physics**

When an object is placed on a ramp; the friction is ,usually, a fraction of the component of weight perpendicular to the ramp. This fraction is call the coefficient of friction(u). Mathematically, Fk = u*Fn where Fn is the Normal and is perpendicular to the ramp. Fk is the ...
*January 19, 2014*

**physics**

mass = 155/1000 = 0.155 kg. V = 95mi/3600s * 1600m/mi = 42.2 m/s. Momentum=m*V = 0.155 * 42.2=6.54 kg.m/s
*January 19, 2014*

**Physics**

16.9m[225o] 33.8m[0o] 50.7m[50.9o] X=16.9*cos225+33.8+50.7*cos50.9=53.8 m. Y=16.9*sin225+0+50.7*sin50.9 = 27.4 m. tan A = Y/X = 27.4/53.8 = 0.50921 A = 27o D = X/cos A = 53.8/cos27 = 60.38 m.
*January 19, 2014*

**physics**

r = (0.5*150)/1000 = 0.075 m Vc=pi*r^2*h=3.14*0.075^2*1=0.01767 m^3 = Vol. of the cylinder. Vs = 2/3 * 0.01767 = 0.01178 m^3 = Vol. submerged = Vol. of water displaced. 0.01178m^3 * 1000kg/m^3 = 11.78 kg = mass of water displaced. m*g = 11.78kg * 9.8N/kg = 115.4 N = Wt. of ...
*January 19, 2014*

**Physics**

See previous post: Sun,1-19-14,2:30PM.
*January 19, 2014*

**Physics**

L = V*T = V/F = 340/170 = 2 m.
*January 19, 2014*

**physics- multiple choice**

1a. 2e. 3c.
*January 19, 2014*

**physics**

X = 10 N. Y = 20 N. tan A = Y/X = 20/10 = 2.0 A = 63.43o R=Y/sin A = 20/sin63.43 = 22.4N[63.43o] a
*January 19, 2014*

**physics**

d = r*t = 14 r = 14/t = 14/(0.0056/2) = 5000 m/s.
*January 19, 2014*

**Science**

a. When they are acting in the same direction. F = 5+7 = 12 N. b. When they are acting in opposite directions. F = 7-5 = 2 N.
*January 19, 2014*

**Maths**

Correction: x = -5. Eq: Y = -5UD
*January 19, 2014*

**Maths**

m = UD X = -5 Y = mx + b Y = UD5 + 0 Y = UD5 Y = 8 is a hor. line. b = 8 = Y-intercept m = 0 = The slope of a hor. line. Use the following points for graphing: (-4,8) (-2,8) (0,8) (2,8) (4,8) Note: Y is constant and does not vary; it remains at 8 for all values of X. y =
*January 19, 2014*

**Physics Please check my answers**

Are all the other correct?
*January 17, 2014*

**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*

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