Tuesday

February 28, 2017
Total # Posts: 13,229

**Math**

(x-2)/x > 1/2. 2x-4 > x, X > 4. Let x = 5. (5-2)/5 = 3/5.

*February 5, 2017*

**math**

A diagram of the problem: 1. Draw a rectangle with the longest sides hor. 2. Draw a hor. line through the ver. sides to form two rectangles. 3. Label the ver. sides of the lower rectangle h1(15m) and the ver. sides of the top rectangle h2. 4. Draw a diagonal from the upper ...

*February 4, 2017*

**math**

Tan 17 = h1/d. Tan 17 = 15/d, d = 49.1 m. = Distance between the buildings. Tan32 = h2/d. Tan32 = h2/49.1, h2 = 30.7 m. = ht. from window of 1st bldg. to top of 2nd bldg. h = h1+h2 = 15 + 30.7 = 45.7 m. = ht. of 2nd bldg.

*February 4, 2017*

**Math**

Yes! -9(x-63) = x + (-49) = x-49.

*February 4, 2017*

**PHYSICS**

A window washer pulls herself upward using the bucket-pulley apparatus.. Part A) How hard must she pull downward to raise herself slowly at constant speed? The mass of the person plus the bucket is 80 kg . Part B) If she increases this force by 16 %, what will her acceleration...

*February 4, 2017*

**physics**

The cable supporting a 2150-kg elevator has a maximum strength of 2.2×104 N . What maximum upward acceleration can it give the elevator without breaking?

*February 4, 2017*

**Physics**

1. V^2 = Vo^2 + 2a*d. (3*10^6)^2 = 0 + 2a*0.15, a = ?. 2. F = M*a, a = F/M = 4.9/0.5 =

*February 3, 2017*

**maths**

(75+82+90+X)/4 = 85. X = ?.

*February 3, 2017*

**physics**

See previous post.

*February 3, 2017*

**physics**

V = pi*r^2*(h2-h1). V = 3.14*6^2*(135-120) = 1696 cm^3.

*February 3, 2017*

**Algebra**

1. (3,2), (1,-4) m = (y2-y1)/(x2-x1) = (-4-2)/(1-3) = -6/-2 = 3. 2. (-2,4), (-4,6). m = (6-4)/(-4-(-2)) = 2/-2 = -1. 3. (7,4), (-5,-2). m = (-2-4)/(-5-7) = -6/-12 = 1/2. Y = mx + b 4 = (1/2)7 + b, b = 1/2. Y = (1/2)x + 1/2. 4. (1,4), (2,-8). m = (-8-4)/(2-1) = -12, Y = mx + b...

*February 1, 2017*

**Math**

3pizzas/4bro. = 3/4 Pizza/bro.

*January 31, 2017*

**Physics**

V1 = a1*t1 = 1.76 * 20 = 35.2 m/s. d1 = 0.5a1*t1^2 = 0.88*20^2 = V2 = V1 + a*t = 35.2 - 5.93*5 = 5.55 m/s. The 5-second deceleration is not enough to bring the car to a full stop. d2 = V1*t + 0.5a*t^2. d2 = 35.2*5 - 0.5*5.93*5^2 = d = d1+d2 =

*January 31, 2017*

**algebra**

14x -3 y to the negative 4 / 2x5 y to the negative 2 how do you do this

*January 31, 2017*

**math**

1. I = Po*r*t = 1200*(0.105/12)*3. 2. P = Po + Po*r*t. P = 1200 + 1200*0.0775*2 = 3. 100%-20% = 80% financed. Po = 0.80 * 69,500 =

*January 31, 2017*

**Math**

4. 30/80 = 6/16. Not 6/18.

*January 30, 2017*

**Math**

1. 4/20 = 1/5. Not 1/6.

*January 30, 2017*

**math**

a. 1957 total CDs. X pop CDs. x-256 hip-hop CDs. (x-256)/3 country CDs. x + (x-256) + (x-256)/3 = 1957. Multiply both sides by 3 and solve for x. c. Country CDs/3.

*January 30, 2017*

**Physics**

V2 = V1 + a*t. 60 = 0 + a*4, a = 15 m/s^2. d = V1*t + 0.5a*t^2. V1 = 0, t = 4 s., a = 15 m/s^2, d = ?.

*January 30, 2017*

**physics**

Mb*V1 + Ma*V2 = Mb*V3 + Ma*V4. 5*3 - 10*3 = 5*V3 + 10*2, -15 = 5V3 + 20, V3 = -7 m/s = 7 m/s to the left.

*January 30, 2017*

**Science**

Incomplete.

*January 29, 2017*

**Science**

A. d = Vo*t + 0.5a*t^2. d = 0 + 1*30^2 = B. V = a*t.

*January 29, 2017*

**physics**

Tan A = (-3.50)/116.5 = -0.030043, A = -1.72o = 1.72o S. of E. Tan1.72 = d/153, d = 4.59 m.

*January 29, 2017*

**Physics**

Range = Vo^2*sin(2A)/g. 2.4 = 7^2*sin(2A)/9.8. A = 14.7o. = Minimum launching angle. Max. range occurs at 45o: Range = 7^2*sin(2*45)/9.8 = 5 m., max. Range of launch angles = 14.7 t0 45o.

*January 28, 2017*

**algebra**

t = 4/8 * 32h =

*January 28, 2017*

**physics**

2. Continued. d = V*t, V = 3*10^5 km/s, t = ?.

*January 28, 2017*

**physics**

1. 10^56/10^35 = 2. d = 3.3AU * 1.499*10^8km/AU =

*January 28, 2017*

**Pre Cal**

A ) B + C = 180. A + 62 + 48 = 180, A = 70o. sinB/b = sinA/a. b = ?.

*January 27, 2017*

**biology**

1)Can you suggest reasons why a phylogeny based on molecular evidence and a phylogeny based on morphology and other evidence might not be exactly the same? 2) Zoologist worldwide are sequencing a mitochondrial gene CO1 (cyctochrome c oxidase subunit), which is found in all ...

*January 27, 2017*

**Physics**

M*g = 300 * 9.8 = 2940 N. = Wt. of furniture. Fk = Force of kinetic friction. F1 = 45 N. F2 = 80*Cos25 = 72.5 N. F1+F2 - Fk = M*a. Fk = ?.

*January 27, 2017*

**Physics**

a. V = Vo + a*t. V = 0, Vo = 15 m/s, t = 0.3 s., a = ?. a will be negative. b. F = M*a. F will be negative.

*January 27, 2017*

**physics**

F = 2N/0.2cm * 2cm = 20 H. Work = F*d.

*January 26, 2017*

**math**

X tickets sold. x/6 children's tickets. 40 seniors tickets. X/2 adult tickets. x/6 + 40 + x/2 = X. x/6 + 40 + 3x/6 = x, 4x/6 - x = -40, -2x/6 = -40, X = 120. x/6 = 120/6 = 20. x/2 = 120/2 = 60 2*20 + 3*40 + 6*60 = $520 Collected.

*January 26, 2017*

**math**

Correction: Ignore the "10".

*January 26, 2017*

**math**

10 100ft^2/2 = 50 ft^2/sq. s^2 = 50, s = 7.071 ft. 7.071ft/side * 8sides = 56.57 ft = total required. But we have only 56 ft.

*January 26, 2017*

**math**

At = Ag + Arg. At = 6 + Arg, We need to know the dimensions of the area surrounding the rose garden. Then we could calculate At, the total area which leaves only one unknown(Arg), the area of the rose garden.

*January 26, 2017*

**Science**

d = V*t.

*January 26, 2017*

**Math**

Flour/Milk = Y/X = 5/4. a. Yes. b. Y/X = 5/4, Y/14 = 5/4, Y = ?.

*January 25, 2017*

**Math**

See previous post: Wed, 1-25-17, 8:22 P.M.

*January 25, 2017*

**physics**

Disp. = -34i + 117 + 64.5i + 28.5 = 145.5 + 30.5i. Magnitude = sqrt(145.5^2+30.5^2) =

*January 25, 2017*

**Math**

Wed.: d = r*t1 = 50mi/h * (43/60)h = 35.83 mi. Thu.: t2 = d/r = 35.83/68 = 0.527 h. = 31.6 min. t1-t2 = 43-31.6 = 11.4 min = Time saved.

*January 25, 2017*

**Physics**

40m/1min = 40m/60s = 0.667 m/s.

*January 25, 2017*

**Math**

5/20 = 1/4. A. = 1/4. D. 25/10 = 1/4.

*January 24, 2017*

**physics**

The positive and negative plates of a parallel-plate capacitor have an area of 1.05 cm by 1.05 cm. Their surface charge densities are +1.00×10-6 C/m2 and -1.00×10-6 C/m2, respectively. A proton moving parallel to the plates enters the middle of the space between ...

*January 24, 2017*

**science**

The system is in equilibrium: 30o W. of N. = 120o CCW. T1*Cos120 = -T2*Cos60. T1 = T2. T1*sin120 + T2*sin60 = -(-10) = 10. T2*sin120 + T2*sin60 = 10, 0.866T2 + 0.866T2 = 10, T2 = 5.77 N. T1 = T2 = 5.77 B.

*January 24, 2017*

**applied mechanics**

Vo = 72000m/3600s = 20 m/s. V = Vo + a*t = 0. 20 + a*5 = 0, a = -4 m/s^2. V^2 = Vo + 2a*d. V = 0, Vo = 20 m/s, a = -4 m/s^2, d = ?.

*January 24, 2017*

**Algebra**

K = (M2-M1)/(d2-d1) = (30-12)/(18-15) = 6 kg/cm . d = (12kg/6kg) * 1cm = 2 cm. L + 2 = 15, L = 13 cm.

*January 24, 2017*

**Science**

F = m*g in Newtons(N). Work = F*d in Joules.

*January 24, 2017*

**Math**

Assuming simple interest: P = Po + I = Po + Po*r*t. P = 6500 + 6500*0.09*4 = 6500 + 2340 = $8840 = Total amt. paid. I = P=Po =

*January 24, 2017*

**Math**

a. d = r*t. b. t = d/t. Eq1: t1 + t2 = 4 1/3 h. = 13/3 h. Eq2: 60t1 + 90t2 = 350 km. Solve the 2 Eqs simultaneously: -60t1 - 60t2 = -260 +60t1 + 90t2 = 350 sum: 30t2 = 90, t2 = 3 h. t1 + 3 = 13/3, t1 = 4/3 = 1 1/3 h. d1 = 60 * 4/3 = d2 = 90 * 3 =-

*January 24, 2017*

**Geometry**

As = 2pir^2 + pi*2r*h. As = (6.28*8^2) + (3.14*16*24) = 1608 m^2.

*January 23, 2017*

**Math**

a. 3:05, and 3:10. b. 5:00, and 6:05. c. 10:00, and 11:00.

*January 23, 2017*

**Maths**

c = X cm. a = x+20 cm. b = x+20 + 50 cm. a + b + c = 270. x+20 + x+20+50 + x = 270. X = ?. b = x+20+50.

*January 23, 2017*

**physics**

T = 2pi*sqrt(L/g). pi = 3.14., L = 1.25 m., g = 9.8 m/s^2.

*January 23, 2017*

**math**

a = b. x+2y = -2x+6y+1. Eq1: 3x-4y = 1. a + b + c = 28. x+2y -2x+6y+1 + 4y = 28. Eq2: -x+12y = 27. Add Eq1 and Eq2, solve for X, and Y: +3x - 4y = 1 -3x + 36y = 81(3*Eq2). sum: +32y = 82, Y = 41/16. In Eq1, replace Y with 41/16, and solve for X: 3x - 4*41/16 = 1, X = 15/4. X...

*January 22, 2017*

**Mathematics**

1. P1 = Po + Po*r*t. P1 = 12,500 + 12,500*0.12*3 = 2. P2 = Po(1+r)^n. Po = 12,500, r = 0.10. n = 1comp./yr. * 3yrs. = 3 compounding periods. P1-P2 =

*January 22, 2017*

**math**

Eq1: 4x + 2y = -2. m1 = -A/B = -4/2 = -2. m2 = m1 = -2. P2 = (-5,-7). Y = mx + b = -7, -2x + b = -7, b = -7+2x = -7 + 2(-5) = -17. Eq2:Y = -2x - 17.

*January 20, 2017*

**physical science**

Fr = -300 + 150 = -150 N. = 150 N. to the left.

*January 20, 2017*

**math**

C = pi*D = 3.14 * 25 = 78.5 in. 5,280ft/mi * 12in/ft. * 360o/78.5in * 295mi =

*January 19, 2017*

**Math**

The altitude(ht.) bisects the vertical angle and the base: 118/2 = 59o. Tan(90-59) = h/5. h = ?.

*January 19, 2017*

**Math**

Concentration = 6*120mg/60mls =

*January 18, 2017*

**Physical Science.**

Displacement is the straight-line distance from the end point to the starting point. The path traveled might not be a straight line. Displacement =< Distance traveled.

*January 18, 2017*

**Algebra**

T = T1*T2/(T1+T2) = 16*15/(16+15) =

*January 18, 2017*

**math**

0nes place = 9. tens place = X. hundreds place = X+1. x + x+1 = 11. X = 5. 659 blocks.

*January 18, 2017*

**Algebra 2**

2 People: 60boxes/10min . = 6 boxes/min. 6 People: (6/2) * 6 = 18 boxes/min. T = 120boxes * 1min/18boxes = 6.67 min.

*January 18, 2017*

**dynamics**

V1 = 400m/20s = 20 m/s. V2 = 400m/30s = 13.33 m/s. a = (V2-V1)/(T2-T1) = (13.33-20)/(30-20) = -0.667 m/s^2. V2 = V1 + 2a*d. 13.33 = 20 - 2*0.667*d. d = ?.

*January 18, 2017*

**physics**

a. M1*V1 + M2*V2 = 2.9*5.4 - 1.5*1.4 = 13.6

*January 17, 2017*

**physics**

V = Vo + a*t. -1.33 = 0 + a*0.96, a = -1.33/0.96 = -1.39 m/s^2. F = M*a = 53.8 * (-1.39) = -74.5 N.

*January 17, 2017*

**math**

a. At =8*11= 88 in^2 = Total area. Ac = pi*r^2 = 3.14 * 1.5^2 = 7.07 in^2. = Area of each circle. As = 3 * 3 = 9 in^2. = Area of a 3 in square in which the circle can be inscribed. At/As = 88/9 = 9.78 or 9 = The number of squares = the number of circles that can be cut. b. 9Ac...

*January 17, 2017*

**Grade 6, percentage**

At beginning of year: X members in art club. 0.4X boys. 0.6X girls. In middle of year: 0.75 * 0.6X = 0.45X girls remaining. 0.4X+8 boys remains. 0.45x + 0.4x+8 = 42. X = 40 At beginning of year.

*January 17, 2017*

**maths**

Insufficient INFO.

*January 15, 2017*

**MATH**

200paces/4sides = 50 paces/side. 50paces/side * 40cm/pace = 2000 cm/side.

*January 15, 2017*

**Math- fractions**

So, we find a common denominator for the two fractions: 2/3 = 8/12, and 3/4 = 9/12.

*January 15, 2017*

**math**

I = Po*r*t = 8000*0.07*5 =

*January 12, 2017*

**Grade 6, percentage**

X members at first. 0.8 * x = 0.8x Male. x - 0.8x = 0.2x Female. After 450 members left: 0.75*0.8x + 0.5*0.2x = x-450. 0.6x + 0.1x - x = -450, X = 1500.

*January 12, 2017*

**Physics**

64.8o W of N = 154.8o CCW. 22.4o W of N. = 112.4o CCW. M1*V1 + M2*V2 = = M1*V3 + M2*V4. 0.4*3.57m/s[154.8o] + 0.45*5.46m/s[90o] = 0.4*4.28m/s[112.4o] + 0.45*V4. 1.43m/s[154.8] + 2.46m/s[90o] = 1.71m/s[112.4] + 045V4, -1.29+0.609i + 2.46i = -0.652+1.58i + 0.45V4, -1.29 + 3.07i...

*January 11, 2017*

**Physics**

L = V*T. 1.3 = 2.5*T, T = ?

*January 11, 2017*

**algebra**

Divide numerator and denominator by 5: (x-1)/(2x^2-5x+3). Factor the denominator: A*C = 2*3 = 6 = (-2)*(-3), 2x^2 - (2x+3x) + 3 = 0, (2x^2-2x) - (3x-3) = 0, 2x(x-1) - 3(x-1) = 0, (x-1)(2x-3) = 0, (x-1)/(x-1)(2x-3) = 1/(2x-3).

*January 11, 2017*

**maths**

Option 1: P = Po + Po*r*t. P = 12,000 + 12,000*(0.08/12)*9 = 12,000 + 720 = $12,720. I = $720. Option 2: Ar = Ab-Ab*r*t. Ar = 12,000-12,000*(0.07/12)*9 = 12,000 - 630 = $11,370 = Amt. received. I = $630. Gary should choose Option 2.

*January 11, 2017*

**Physics**

See previous post: Wed, 1-11-17, 12:49 PM.

*January 11, 2017*

**Physics**

F = M*g = (80+20)*9.8 = Work = F*d.

*January 11, 2017*

**Physics**

d = 0.5g*t^2 = 4.9*1^2 = 4.9 m.

*January 11, 2017*

**Trig/PreCalc**

Vr = 425mph[160o] + 75mph[200o]. X = 425*cos160+75*cos200 = -470 mph. Y = 425*sin160+75*sin200 = 120 mph. Tan A = Y/X = 120/-470 = -0.25532. A = -14.3o. = 14.3o N. of W. = The direction. Vr = -470/-Cos14.3 = 485 mph. = Resultant speed.

*January 10, 2017*

**Science**

F=M1*a1. M1 = F/a1 = 400/2 = 200 kg. M2 = F/a2 = 400/13 = 30.8 kg. a = F/(M1+M2).

*January 10, 2017*

**Physics**

The two numbers cannot be added directly, because they are 90o out of phase: V = 300 + 400i. You only want the magnitude: V = sqrt(300^2+400^2) = 500 m/s.

*January 10, 2017*

**Physics**

M*g = 30 * 9.8 = 294 N. Fp = 294*sin30 = 147 N. = Force parallel with slide. Fn = 294*cos30 = 254.6 N. = Force perpendicular to the ride = Normal. Fk = u*Fn = 0.15 * 254.6 = 38.2 N. = Force of kinetic friction. Fap = 200 N. = Force applied. Fap-Fp-Fk = M*a. 200-147-38.2 = 30*a...

*January 10, 2017*

**Physics**

a,b. M1*V1 + M2*V2 = M1*V3 + M2*V4. 1*5 + 1*0 = 1*4[37o] + 1*V4. 5 = 4[37o] + V4, V4 = 5-4[37O], V4 = 5-4*Cos37-4*sin37 = 5-3.19-2.41i = 1.81 - 2.41i = 3.01m/s[-53.1o] = 3.01m/s[53.1o] S. of E. = Velocity and Direction. c. A1+A2 = 37 + 53.1 = 90.1o.

*January 9, 2017*

**Math**

D. 12/15 = 4/5, 30/50 = 3/5. The ratios must be equal to form a true proportion.

*January 8, 2017*

**physics**

M*g = 225, M = 225/g = 225/9.8 = 23 kg. F = M*a, a = F/M = 14.5/23 = 0.630 m/s^2.

*January 8, 2017*

**physics**

The system is in equilibrium: T1*sin15.4 + T2*sin A = +253. 459*sin15.4 + T2*sin A = 253, 121.9 + T2*sin A = 253. T2 = (253-121.9)/sin A = 131.1/sin A. -T1*Cos15.4 + T2*Cos A = 0, -459*Cos15.4 + T2*Cos A = 0. T2*Cos A = 459*Cos15.4 = 442.5, (131.1/sin A)Cos A = 442.5, 131.1*...

*January 8, 2017*

**Science**

M/W.

*January 8, 2017*

**Physics**

Density = 100g/150cm^3 = 0.667 g/cm^3.

*January 8, 2017*

**Physics**

Vb = 0.85 * 250 = 212.5 cm^3 = Vol. below surface. = Vol. of water displaced. V*D = 212.5cm^3 * 1g/cm^3 = 212.5 grams of water displaced. Upthrust = M*g = 0.2125 * 9.8 = 2.08 N.

*January 8, 2017*

**Math**

8/(2/3) = 8 * 3/2 = 12. pieces.

*January 8, 2017*

**Science(physics)**

V = (V1+V2)/2 = (15+25)/2 = 20 km/h.

*January 8, 2017*

**Science(physics)**

A boy while driving to his school covers at the average speed of 15km/h.On his return trip along the same route, covers at the average speed of 25km/h due to less traffic.What is the average speed for the whole trip

*January 8, 2017*

**Finance**

P = Po(1+r)^n = 83,190. r = APR expressed as a decimal. n = The number of compounding periods. 30,000(1+r)^9 = 83,190. (1+r)^9 = 83,190/30,000 = 2.773, 9*Log(1+r) = Log2.773, Log(1+r) = Log2.773/9 = 0.0492, 1+r = 10^(0.0492) = 1.12, r = 1.12-1 = 0.12 = 12%.

*January 6, 2017*

**physics**

M*g = Wt. of car. a. Fn = Mg*Cos17 = 0.956Mg. Fn/Mg = 0.956Mg/Mg = 0.956. b. Fn = Mg*Cos30 = 0.866Mg. Fn/Mg = 0.866Mg/Mg = 0.866.

*January 5, 2017*

**physics**

Car A: 0.5a*Ta^2 = 400 m. 0.5*11*t^2 = 400. Ta = ?. Car B: 0.5*11.8*Tb^2 = 400. Tb = ?. b. T = Ta-Tb.

*January 5, 2017*