# Posts by henry

Total # Posts: 13,578

**math**

Thanks, Reiny! I see my mistake now: I should have added instead of multiplying.

**math**

John is X yrs. old. Pamela is (X-8) yrs. old. 5x + 5(x-8) = 40. X = ?, (x-8) = ?. The numbers don't add-up; check your problem for typos.

**Math**

There are 52 white keys on a piano. The lowest key is A. The keys are designated A, B, C, D, E, F, and G in succession, and then the sequence of letters repeats, ending with a C for the highest key. a) If five notes are played simultaneously, in how many ways could the notes ...

**Physics**

M*g = 103 N. = Wt. of box. M = 103/g = 103/9.8 = 10.5 kg. Fn = 103*Cos 0 + 25 = 128 N. = normal force. Fk = u*Fn = 128u. Fx-Fk = M*a. 20-128u = 10.5*(-0.9), u = ?.

**math**

Tan A = h/L = 10/20 = 0.5. A = ?.

**algebra**

X Qtrs.. 77-x nickels.. 25x + 5(77-x) = 1385 cents. X = ?, 77-x = ?.

**Maths**

r= 0.8m/0.5s = 1.6 m/s.

**Physics**

d = V*t. 170 = V*1.1, V = ?.

**physics**

Let M1 = 2kg. M2 = 1 kg. W1 = F1*d1 = (M1g)*(25-5) = (2*9.8)*20 = W2 = (1*9.8)*(24-14) = W1/W2 =

**physics**

Power = F*d/t = Mg*d/t = 588*10/8 = 735 J/s = 735 Watts.

**physics**

My answer is A.

**physics**

My answer is C.

**Physics**

1. M1*V1 + M2*V2 = M1*V + M2*V. 1000*50 - 1000*20 = 1000V + 1000V, 30,000 = 2000V, V = 15 m/s. 3. Momentum = 2000*50 - 2000*20 = 60,000 kg*m/s.

**Physics PLEASE HELP**

Correction: Please disregard the solution in part b.

**Physics PLEASE HELP**

a. Mg = (2220+3220)*9.8 = 53,312 N. = Wt. of the barges. Fap = 34,000 N. Fk = 8,000 + 10,000 = 18,000 N. Fap-Fk = M*a. 34,000-18,000 = 5440*a, a = ?. b. (M1+M2)*g =

**comsumer math**

9. 1151.65/mo. * 4mo. = $4606.60 = Amt. saved. I = Po1*r1*t + Po2*r2*t. Po1 = 0.25*4606.60 = $1151.65. Po2 = 0.75*4606.60 = $3454.95. I = 1151.65*(0.033/360)*60 + 3454.95*(0.043/360)*60 = 6.33 + 24.76 = $31.09 Total. 10. I = 4606.60*(0.033/360)*60 = $25.34. Diff. = 31.09-25.34...

**Physics**

Please proof-read your problem.

**trigonometry**

Vr = 185km/h[120]+32km/h[165]. X = 185*Cos120 + 32*Cos165 = -123.4 km/h. Y = 185*sin120 + 32*sin165 = 168.5 km/h. Tan A = Y/X = 168.5/(-123.4) = -1.36548, A = -53.8o = 126.2 CCW. Vr = Y/sin(126.2) = 168.5/sin(126.2) = 209km/h[126.2o].

**geometry**

Please proof-read your work. L = 25*Cos36 = W = 25*sin36 = Ar = L*W. = Area of rectangle. Pr = 2L + 2W. At = 0.5L*W = Area of triangle. Pt = L+W+25.

**Personal Finance**

P = Po + Po*r*t. t = 90days/360days = 0.25 yrs. 100 = 95 + 95*r*0.25. r = ?.

**math algebra, please check my answers**

1. Given: m = 3/4. P(4,7). Y = mx + b. 7 = (3/4)4 + b, b = 4 = Y-intercept. P1(0,4). 2. X/Y = Z. X = 0. If Y = 0, X/Y would be undefined. I'm assuming "a" is a constant. 3. (2x^2+4x-30)/(x-3) = 2(x^2+2x-15)/(x-3) = 2(x-3)(x+5)/(x-3) = 2(x+5). 4. Cubic inches. 5...

**Álgebra**

The lateral area is the sum of the areas of all of the vertical sides(4). Lateral Area = 2(W*h) + 2(L*h).

**Science**

Incomplete.

**Phyiscs**

Incomplete.

**Maths**

1. P = Po*(1+r)n. Po = $300.000. r = 0.12/12 * 2mo. = 0.02 = Bi-monthly % rate expressed as a decimal. n = 6comp./yr. * 3yrs. = 18 Compounding periods. 300,000 = Po(1+0.02)^18. Po = 300,000/1.02^18 = $210,048. 2. Same procedure as #1 except for 5 yrs. and $500,000.

**Science**

g = 9.8 m/s^2 on earth. g = 1.6 m/s^2 on the moon. So the wt. of an object is less on the moon because the acceleration due to gravity is less. Wt. = M*g. The mass doesn't change.

**Math**

A. (15dogs/12cats) * 100% = B. ((15-3)/15) * 100% = C. Questions B and C are identical. D. E. 0.14 * 33 = 4.62?. Check your problems for accuracy.

**math**

a. M = 64grams/4wafers = 16 grams = 0.016 kg. b. Wafers = 4wafers/0.016kg * 3.2kg =

**physics**

M*g = 25 * 9.8 = 245 N. = Wt. of child. At bottom of slide: a. PE = Mg*h = 245*4 = 980 J. b. KE = 0.5M*V^2 = 0.5*25*5^2 = 312.5 J. c. PE-KE = Energy lost to friction.

**Physics**

h = 0.5g*t^2. 54 = 4.9t^2, t = 3.32 s. = Fall time. d = V*t, 130 = V*3.32, V = ?. V in m/s.

**math**

Remainder = 8/8 - 1/8 = 7/8. a. 1/2 * 7/8 = 7/16 of the money. b. 7/8 - 7/16 = 14/16 - 7/16 = 7/16 Remaining. c. 7/16 * $240. =

**Math**

15. 0.42 * 175 = 18. 100% + 15% = 115%. 1.15 * 15.50 = 19. Tax = 0.07 * 550 = 20. Discount = 0.4 * 160 =

**Math**

10. 3.6/8 = Y/5. 11. 0.65, 13/20. 13. 1 - 5/25 = 5/5 - 1/5 = 4/5 = 0.80 = 80%. 14. L/W = 8/4 = 20/W. W = ?.

**Math**

9. d = 25mi/in * 3.4in =

**Math**

1. (8+12+14)/8 2. 45/60. 3. d = 226mi/2h * 8h = 4. 82.15/31gal. 5. Cost = 0.65/Lb * P. 1.95 = 0.65P. P = ?. 6. 6/27 = 2/9. 7. Y/22 = 3/11. Multiply both sides by 22: 8. 1/6 = 8/x Cross-multiply:

**Math**

Let S1 = S2 = S3 = S4 = 10 units. A1 = L*W = 10 * 10 = 100 sq. units. S1 = S3 = 1.5*10 = 15. S2 = S4 = 0.5*10 = 5. A2 = L*W = 15 * 5 = 75 sq. units. A2/A1 = 75/100 = 0.75 = 75%. P2/P1 = (2L+2W)/(4*10) = (2*15+2*5) = 40/40 = 1.00 = 100%.

**Physics-Work, Energy, and Power**

At the top of hill: PE = M*g*h = 56.9 * 9.8 * 8.21 = 4578 J. At bottom of hill: KE = PE - Fk*d. 0.5M*V^2 = 4578 - 11.7*31.7 0.5*56.9*V^2 = 4207, V^2 = 148, V = 12.2 m/s.

**Physics**

R = (1.72*10^-80/2.82*10^-8) * 0.527 Ohms = 0.321 Ohms.

**Physics**

R = Ro + a(T2-T1)*Ro. 55.6 = 31.8 + a(53-28)31.8. 55.6 = 31.8 + 795a, a = 0.03/deg. C = Temp. coefficient.

**physics-sound**

Fd = (Vs+Vd)/(Vs-Vp) * Fp. Fd = (343+17)/(343-41) * 800. = 953.6 Hz. = Freq. heard by driver of the truck. Change = 953.6 - 800 = 153.6 Hz.

**physics**

A. Fg = (Vs+Vg)/(Vs-Vp) * Fp. 578 = (343+0)/(343-Vp) * 475. 578 = 343/(343-Vp) * 475, Divide both sides by 475: 1.21 = 343/(343-Vp), 416-1.21Vp = 343, Vp = 60.3 m/s. B. Fg = (Vs-Vg)/(Vs+Vp) * Fp. Fg = (343-0)/(343+60.3) * 475. Since the distance between the people on the gnd. ...

**Physics**

M1*V1 + M2*V2 = M1*V + M2*V 0.08*50i+0.06*50j = 0.08V+0.06V. 4i + 3j = 0.14V. 5[36.9o] = 0.14V, V = 35.7m/s[36.9o]. KE before the collision: KE1 = 0.5M1*V1^2 + 0.5M2V2^2. i^2 = 1, j^2 = 1. KE after the collision: KE2 = 0.5M1*V^2 + 0.5M2*V^2. KE(Lost) = KE1-KE2.

**Math**

A. Y/X = 6/3 = 2/1, Y = 2x. 2/3 = 2x, X = 1/2 * 2/3 = 2/6 = 1/3. B. F = M*a, 25 = M*1.25, M = 28 kg.. F = M*a. 35 = 28*a, a = ?.

**Science**

a. V^2 = Vo^2 + 2g*h1. Vo = 0. b. V^2 = Vo^2 + 2g*0.5h1. Vo = 0.

**Science**

1. Vo = 15m/s[60o]. Yo = 15*sin60 = 13 m/s. Y^2 = Yo^2 + 2g*h. 0 = 13^2 - 19.6h. h = ?. 2. h = 4.9*t^2. 1.8 = 4.9t^2, t = ?. d = V*t. d = 8*t.

**Science**

1. h = 4.9t^2. 12.5 = 4.9t^2. t = ?. d = V*t. d = 8*t. 2. Y = Yo + g*t. Yo = 0, g = 9.8 m/s^2, t = Value cal. in prob. 1.

**Maths**

Wage = 40*18.60 + 6.5*1.5*18.60 + 4*2*18.60 =

**maths**

P = 6 + 6 + 6 = 18 cm. P/2 = 18/2 = 9 cm. S1/2 = S2/2 = S3/2 = 6/2 = 3 cm. At = sqrt(9*3*3*3) = 15.6 cm^2 = 5pi = Area of triangle. Ac > 5pi = 12pi.

**Physics**

M*g = 10 * 9.8 = 98 N. = Wt. of box. Fp = 98*sin 0 = 0. = Force parallel with the surface. Fn = 98*Cos 0 - T*sin45 = 98 - 0.707T = Normal force. Fk = u*Fn = 0.5(98-0.707T) = 49-0.354T. T*Cos45-Fp-Fk = M*a 0.707T-0-(49-0.354T) = 10*1, 0.707T+0.354T = 59, T = 55.6 N.

**Physics**

M*g = M*9.8 = 9.8M = Wt. of skier. Fp = 9.8M*sin30 = 4.9M. = Force parallel with slope. Fn = 9.8M*Cos30 = 8.49M = Normal force. Fk = u*Fn = u*8.49M. Fp-Fk = M*a. 4.9M-u*8.49M = M*2 = 2M, u*8.49M = 2.9M, u = 0.342.

**Math**

A. Y = mx + b. Y = (-2/3)X + 4. B. ax + by = c. (0,-2), (3,0). m = (0-(-2))/(3-0) = 2/3. Y = mx + b. Y = (2/3)x - 2, -2x/3 + y = -2, Multiply both sides by -3: 2x -3y = 6. STD. form. C. m = -3, P(1,2). Y = mx + b. 2 = -3*1 + b, b = 5. Eq: Y = -3x + 5.

**math**

Tan45 = h/d, h = d*Tan45. Tan75 = h/(d-50), h = (d-50)*Tan75. Therefore, h = d*Tan45 = (d-50)*Tan75. d*Tan45 = (d-50)*Tan75. divide both sides by Tan75: 0.268d = d-50, d-0.268d = 50, d = 68.3 m. h = d*Tan45 = d = The hor. distance between point A and the foot of the tower.

**Math**

A. Ao = 7.5*15 + 585 = $697.50 = Initial amount. Y = 697.5 - 7.5x Y = -7.5x + 697.5. P1(X1,Y1) = (15,585). Y-Y1 = m(X-X1). Point-slope form. Y-585 = -7.5(X-15). B. Y = mx + b. Slope-intercept form. Y = -7.5x + 697.5. C. Y = -7.5*52 + 697.5.

**Algebra**

1st hiker walks X mi/h. 2nd hiker walks (x+2.2) mi/h. d1 + d2 = 22 miles. sx + 5(x+2.2) = 22. X = ?.

**physics**

I saw the answer 0.04 but I don't know how they arrive at that answer

**Math**

L = 3.5 Ft. W = 18 1n. = 1.5 Ft. h = 2 Ft. As = 2(W*h) + 2(L*h) + 2(L*W). As = Surface area.

**Trigonometry**

X^2 + Y^2 = C^2. x^2 + 7^2 = 25^2, x^2 = 25^2 - 7^2 = 576, x = 24. If Cos C is negative, X is negative. Cos C = (-24)/25 = -0.96, C = 163.7o CCW from +x-axis. = 73.7o W. of N. P(-24,7).

**Algebra**

X is unknown until the Eqs has been solved. N or any letter can be used for the unknown. 1. 3x + 7 = -15. Isolate 3x by subtracting 7 from both sides: 3x+7-7 = -15-7, 3x = -22, divide both sides by 3: X = -22/3 = -7 1/3. 2. -2x - 6 = 12. -2x-6 + 6 = 12 + 6, -2x = 18, X = 18/-2...

**Math**

If a boat was 36' long and i built a model of it 18" long what scale would the model be

**physics**

Density = 0.72*Density of water. Density = 0.72 * 1000kg/m^3 = 720kg/m^3.

**Maths**

Cost of a cup = $X. Cost of a plate = $Y. Y = 4x.

**Science**

F = M*a. 5 = 10*a, a = 0.5 m/s^2. a = (V-Vo)/t. 0.5 = 2/t, t = 4 s.

**Math**

Exponential growth(n^10) is greater.

**Álgebra**

360o/8sections * 3sections =

**physics**

V^2 = Vo^2 + 2a*d. 0 = (29.17)^2 - 500*d, d = ?.

**Algebra**

1 st integer = X. 2nd integer = x+1. 3x + 4(x+1) = 95. x = ?.

**maths**

P1 = 2L + 2W = 2*15 + 2*10 = 50 M. = P2. W/L = 4/5. W = 0.8L. P2 = 2W + 2L. P2 = 2*0.8L + 2L, 50 = 1.6L + 2L, L = 13.9 M. W = 0.8L = 0.8*13.9 = 11.1 m.

**Math**

X = The # of min. used. C = Total cost. Plan A: C = 0.1x. Plan B: C = 0.075x + 10.

**Physics**

30o W. of N. = 120o CCW from + x-axis. The system is in equilibrium: A*Cos120 = - B*Cos (0). A = -B*Cos(0)/Cos120 = 2B. A*sin120 = -(-200), A = 200/sin120 = 231 Lbs. A = 2B, 231 = 2B, B = 115.5 Lbs.

**physics**

A. X = -23*125 = -2875 m. Y = -12*255 = -3060i. Disp. = sqrt(x^2+y^2). B. Tan A = Y/X. A = ?. = Direction.

**physics**

Vo = 17m/s[39o]. Xo = 17*Cos39 = 13.2 m/s. Yo = 17*sin39 = 10.70 m/s. A. d = Xo*t. 3.8 = 13.2*t, t = 0.288 s. B. h = Yo*t +0.5g*t^2. h = 10.7*0.288 - 4.9*0.288^2 = 2.67 m.

**Science**

A. Work = F * d. They did the same amount of work. B. Power is the rate of doing work: P = F * d/t. The one that took the least time used the most power.

**Vectors**

50o W. of N. = 140o CCW. Vr = Vb + Vc. 20[140] = Vb + (-8i), Vb = 20[140] + 8i, Vb = 20*Cos140+20*sin140 + 8i. Vb = -15.3 + 12.9i + 8i = -15.3 + 20.9i Tan A = Y/X = 20.9/(-15.3) = -1.36601. A = -53.8o = 53.8o N. of W. = 126.2o CCW = 36.2O W of N.

**Vectors**

B. sin50 = 1.7/d. d = 2.22 km.

**Vectors**

Your last question doesn't make sense.

**Vectors**

A. Vr = Vb + Vc. 20[50o] = Vb - 8i, Vb = 20[50]+8i, Vb = 20*Cos50+20*sin50 + 8i, Vb = 12.9 + 15.3i + 8i = 12.9 + 23.3i. Tan A = Y/X =23.3/12.9 = 1.80620, A = 61o.

**Math**

3n = 5n-14. n = ?.

**math**

The opposite angles of a parallelogram are equal: A = C = 35 + 25 = 60o. 360-120 = 240o. B = D = 240/2 = 120o.

**Maths**

$5400 * 1m/$13.50 = 400 m. Cost = 400m * 28.50/m =

**Algebra**

Po1*r1*t + Po2*r2*t = 2730. Po1*0.06*1 + Po2*0.09*1 = 2730, 0.06Po1 + 0.09Po2 = 2730. Eq1: 6Po1 + 9Po2 = 273,000, Eq2: Po1 + Po2 = 39000. Multiply Eq2 by -6 and Add: +6Po1 + 9Po2 = 273000. -6Po1 - 6Po2 = -234,000. Sum: 3Po2 = 39,000, Po2 = $13,000 Invested in acc. #2. Po1 = 39...

**Physics**

post it.

**Physics**

V = 80m/s[-20O]. Vx = 80*Cos(-20) = 75.2 m/s. Vy = 80*sin(-20) = -27.4 m/s. A. Range = V^2*sin(2A)/g. Range = 80^2*sin(2*20)/9.8 = 420 m. B. Tan20 = h/420, h = 153 m. h = Vy*t + 0.5g*t^2. 153 = -27.4*t + 4.9t^2, 4.9t^2 - 27.4t - 153 = 0, Using the Quadratic Formula: t = 9.04 s...

**Math**

L = 23.5 ft. W = 11 ft. h = 2/3 ft. 1 yd^3. = 27 ft^3. V = L*W*h. Yards = V/27.

**physics**

Incomplete.

**electronic**

Incomplete.

**physical science**

R = pL/A. p = 110*10^-8 Ohm.m = 110*10^-6 ohm.cm. L = 220 cm. r = 0.056 cm. A = pi*r^2 = 3.14*0.056^2 = 9.85*10^-3 cm^2. R = (110*10^-6*220)/(9.85*10^-3) = 2.46 Ohms.

**pyhsical science**

R = pL/A A = pi*r^2 = pi*(2r)^2 = pi*4r^2. R2 = 2pL/(pi*4r^2) = pL/Pi*2r^2.

**Maths**

Wt. of box = 20 N. Fp1 = 4*Cos20 = 3.76 N. = Force acting Parallel to ramp(upward). Fp2 = 20*sin A = Force acting parallel to ramp(downward). Fp2-Fs-Fp1 = 0. 20*sin A-5-3.76 = 0. Equilibrium. A = ?. 9 20*sin A-5-3.76 = 0. 20*sin A = 8.76, A = 10.8o. = Angle of elevation.

**algebra**

1. a^2 + b^2 = c^2. 15^2 + b^2 = 20^2, 225 + b^2 = 400. b^2 = 400-225 = 175, b = sqrt(25*7) = 5*sqrt7. 2. 9^2 + 12^2 = c^2. c^2 = 81 + 144 = 225, c = sqrt(225) = 15.

**Algebra**

Eq1: A = x * y = 48ft^2. Eq2: P = 2x + 2y = 28 Ft.

**Scienc**

2. Acceleration. 3. A. 6. D. Friction opposes motion. 7. A. Velocity includes magnitude and direction. 8. A. 10. C. 11. F = M*a = 3 * 7 = 21 N.

**Math**

A. V(t) = Vo - 899t. Vo = Initial value. B. V(t) = Vo + 899t.

**Science**

M*g = 50 * 9.8 = 490 N. = Wt. of box. Fp = 490*sin30 = 245 N. = Force parallel with incline. Fn = 490*Cos30 = 424 N. = Normal force. Fs = u*Fn = = 424u. = Force of static friction. Fp-424u = M*a. 245-424u = M*0 = 0, U = ?.

**Physics**

1 gal. = 8 Lbs. = 3.63 kg. M = 10,000gal * 3.63kg/gal. = 36,320 kg. PE = M*g*h = 36,320*9.8*61.5 Joules.

**physics**

V*a*(T2-T1) = 136. 1.53*a*(15.1-92.2) = 136, a = ?.

**physics**

a = 13*10^-6/oC = Temp. coeff. h*a*(T2-T1) = 0.197. h*13*10^-6(40-(-9)) = 0.197, h*0.000637 = 0.197, h = 309.3 m.

**physics**

a = 13*10^-6/deg.C = Temp. coeff. 358*a*(T2-T1) = 358*13*10^-6*(22-1.99) = 0.093 m. = 9.3 cm.

**Math 115**

C = 0.79P, P>100.

**physics**

d = 0.5a*t^2. 8 = 0.5a*4^2, a = 1 m/s^2. V = Vo + a*t.= 0 + 1*4 = 4 m/s.

**physics**

(14*10^-6/19*10^-6) * 3600cm = 2653 cm.