Friday

July 3, 2015

July 3, 2015

Total # Posts: 10,680

**physics**

a. a = (V-Vo)/t. V = 510 m/s Vo = 0 t = 2.37 s. b. a = (V-Vo)/t V = 0 Vo = 510 m/s. t = 3.15 s. Note: Acceleration when braking will be negative.
*November 4, 2014*

**physics**

V^2 = Vo^2 + 2g*h. Vo = 0 @ top of hill. V^2 = 2g*h. Solve for V.
*November 4, 2014*

**physics**

V^2 = Vo^2 + 2g*h = 0 + 19.6*2000 = 3920 V = 62.6 m/s. KE = 0.5m*V^2 = 50*62.6^2 = 195,938 J.
*November 4, 2014*

**physics**

m*g = 180kg * 9.8N/kg = 1764 N. PE = mg*h = 8000 J @ top of hill. h = 8000/mg = 8000/1764 = 4.54 m.
*November 4, 2014*

**Math**

(40/360) * 2p1 = 2pi/9 Radians.
*November 4, 2014*

**Science**

a = (Fap-Ff)/m = (25-6)/1.5 =
*November 4, 2014*

**Physics**

A vector quantity shows magnitude and direction: 50 m/s @ 45o. Magnitude = 50 m/s. Direction = 45 Degrees.
*November 4, 2014*

**physics**

F1+F2+F3 = 72.7N[0o] + 79.9N[45o] + 103N[315o]. X = 72.7 + 79.9*Cos45 + 103*Cos315=202 N Y = 79.9*sin45 + 103*sin315 = -16.33 N. F^2 = X^2 + Y^2 = 202^2 + (-16.33) = 41,071 F = 203 N. = Resultant force. Tan A = Y/X = -16.33/202 = -0.08084 A = -4.62o = 4.62o S. of E. = Direction.
*November 3, 2014*

**science**

1. The DF increases: DF = PW/PRF. 2. The PRF increases: PRF = 1/PRP. 4. When WL decreases, the PRF increases. The increase in PRF decreases the DF. PRF = V/WL
*November 3, 2014*

**physics**

A = (27.1-9.1)*7.7*10^-4 * 5 = 0.0693 Gal.
*November 3, 2014*

**science**

incomplete.
*November 3, 2014*

**Physics**

D = 4.19*Cos10.4
*November 3, 2014*

**Physics**

D = 4.19*sin10.4 =
*November 3, 2014*

**physics**

a. m*g = 1.0*10^4 N. m = 1.0*10^4/g = 1.0*10^4/9.8 = 1020 kg. Fp = 1.0*10^4*sin34 = 5592 N. = Force parallel to the hill. a = Fp/m = 5592/1020 = 5.48 m/s^2. b. V^2 = Vo^2 + 2a*d = 0 + 10.96*28 = 307 V = 17.5 m/s.
*November 2, 2014*

**Physics**

Vo = 20m/s[50o] Xo = 20*cos50 = 12.9 m/s Yo = 20*sin50 = 15.3 m/s. V = Vo + g*Tr = 0 @ max Ht. Tr = -Yo/g = -15.3/-9.8 = 1.56 s. = Rise time. h = Yo*Tr + 0.5g*Tr^2 h max = 15.3*1.56 - 4.9*1.56^2=11.9 m. h = 0.5g*t^2 = 11.9-3.04 = 8.90 m. 4.9t^2 = 8.90 t^2 = 1.82 Tf = 1.35 s...
*November 2, 2014*

**physics**

Vo = 50m/s[30o] Xo = 50*Cos(30) = 43.3 m/s. Yo = 50*sin(30) = 25 m/s. h = Yo*t + 0.5g*t = 59 m. 25t + 4.9t^2 = 50 4.9t^2 + 25t - 50 = 0 Use Quadratic Formula. Tf = 1.54 s. = Fall time. Dx = Xo * Tf = 43.3m/s * 1.54s = 66.7 m. From the cliff. Y = Yo + g*t = 25 + 9.8*1.54 = 40.1...
*November 2, 2014*

**Physics**

a. Fr = 328N[35o] + 464N[13o] X = 328*Cos35 + 464*Cos13 = 721 N. Y = 328*sin35 + 464*sin13 = 293 N. Fr^2 = X^2 + Y^2 = 721^2 + 293^2 = 605,690. Fr = 778 N. = Resultant force. b. a = F/m = 778/2950 = 0.264
*November 2, 2014*

**Physics**

Maximum power transfer occurs when the resistance of the load is equal to the internal resistance of the source: R = r.
*November 2, 2014*

**physics**

Vo = 0 V = 6,000rad/min = 6,000rad/60s = 100 rad/s. a = (V-Vo)/t = (100-0)/4 = 25 rad/s^2
*November 2, 2014*

**Physics**

a. D = Vo*t = 190rad/s * 13s = 2470 rad b. D = 300rad/s * 13s = 3900 Rad. c. a = (V-Vo)/t = (300-190)/13 = 8.46 rad/s^2. D = Vo*t + 0.5a*t^2 D = 190*13 + 4.23*13^2 = 3185 Rad.
*November 1, 2014*

**physics**

Multiply your answer by 100 to convert to cm.
*November 1, 2014*

**physics**

d = 0.5g^t^2. g = 9.8 m/s^2, t = 0.29 s. Solve for d.
*November 1, 2014*

**Physics**

Momentum = m1*V1-m2*V2 = 0.062*9-0.006*4 = 0.558 - 0.024 = 0.534 m1*V = 0.534 0.062*V = 0.534 V = 8.61 m/s.
*October 31, 2014*

**Physics**

Fr = F1 + F2 + F3 + F4 = 0 100N[37o] + 200N[270] + 250N[200] + F4=0 X = 100*Cos37+200*Cos270+250*Cos200 = -155 N. Y = 100*sin37+200*sin270+250*sin200 = -225 N. Tan Ar = Y/X = -225/-155 = 1.45161 Ar = 55.44o = Reference angle. A = 55.44 + 180 = = 235.4o F1+F2+F3 = Y/sin A = -...
*October 31, 2014*

**Physics**

a.m2*V2-m1*V1 = 0.250*10[71o]-0.250*28.4[58.8o] = 2.50[71o] - 7.1[58.8o] X = 2.50*Cos71 - 7.1*Cos58.8 = -2.86 Y = 2.50*sin71 - 7.1*sin58.8 = -3.71 M^2=X^2 + Y^2 = (-2.86)^2 + (-3.71)^2 = 21.9 M = 4.68 = Magnitude of change in momentum. b. Tan Ar = Y/X = -3.71/-2.86 = 1.29720 ...
*October 31, 2014*

**Physics**

(m1+m2)*V = m1*V1 (1424+1424)*V = 1424*11 2848V = 15,664 V = 5.5 m/s.
*October 31, 2014*

**Science Physics**

a. Vw = L*W*h = 85 *30 * (15-3) = 30,600 Ft^3. b. 30,600Ft^3 * 62.4Lbs/Ft^3 = 1.909,440 Lbs. = 955 Tons = Wt. of water displaced. Load = 955 - 160 = 795 Tons.
*October 31, 2014*

**Algebra 1B**

Width = W in. Length = (2W + 4) in. V = L * W * h = 2720 n^3. (2W+4) * W * 17 = 2720 2W^2+4W)*17 = 2720 34W^2 + 68W - 2720 = 0 W^2 + 2W - 80 = 0 -80 =-8*10. (W-8)(W+10) = 0 W-8 = 0 W= 8 W+10 = 0 W = -10 Use positive value of W: W = 8.
*October 31, 2014*

**physics**

T^2 = 4*pi^2*(L/g) T^2 = 39.48(0.65/9.8). Solve for T.
*October 31, 2014*

**algebra 2**

h = 16 - (16-12)/0.5h h = 16 - 8in/h Eq: h(t) = 16 - 8t
*October 31, 2014*

**physics**

a = 0 @ constant speed.
*October 30, 2014*

**physics**

Vo = 17 m/s V = 40 m/s t = 10.7 s. a = (V-Vo)/t. Solve for a.
*October 30, 2014*

**physics**

Vo = 0 a = 4.5 m/s^2 t = 7.9 s. d = ? V = Vo + a*t = 0 + 4.5*7.9 = 35.6 m/s. V^2 = Vo^2 + 2a*d = 35.6^2 Vo^2 + 2a*d = 35.6^2. Solve for d.
*October 30, 2014*

**physics**

V = ? Vo = 0 a = 0.557 m/s^2 d = 5.85 m. V^2 = Vo^2 + 2a*d. Solve for V.
*October 30, 2014*

**physics**

Vo = 0 V = ? t = 5.4 s. a = (V-Vo)/t = 2.57 m/s^2 (V-0)/5.4 = 2.57. Solve for V.
*October 30, 2014*

**physics**

D = Vo*t + 0.5g*t^2 D = 208*2.6 - 4.9*2.6^2 =
*October 30, 2014*

**Fluid Mechanics**

A flat-bottom river barge is 30.0 ft wide, 85.0 ft long, and 15.0 ft deep. (a) How many ft3 of water will it displace while the top stays 3.00 ft above the water? (b) What load in tons will the barge contain under these conditions if the empty barge weighs 160 tons in dry dock?
*October 30, 2014*

**Physics**

m*g = 0.5kg * 3.8N/kg = 1.9 N.
*October 30, 2014*

**math**

T = Time in seconds. h = Ht. in feet. (T, h) (0,100) Platform. (0.5,136) (1.0,164) (1.5,184) (2.0,196) V(2.5,200) Max. point. (3.0,196) (3.5,184) (4.0,164) (4.5,136) (5.0,100). Platform.
*October 29, 2014*

**math**

T = (d/2)/r1 + (d/2)/r2 = 35 min=2100 s. = (d/2)/4 + (d/2)/3 = 2100 = d/8 + d/6 = 2100 Multiply both sides by 24: 3d + 4d = 50,400 7d = 50,400 d = 7,200 m.
*October 29, 2014*

**Physics**

V^2 = Vo^2 + 2g*h = 0 @ max ht. h max = -(Vo^2)/2g = -(2.3^2)/-19.6 = 0.270 m. Since the max ht. is only 0.27 m, the ball cannot be spiked at o.8 m. Please check the numbers for accuracy.
*October 29, 2014*

**physics**

a. Balll #1: V = Vo + g*Tr = 0 @ max Ht. Tr = -Vo/g = -25/-9.8 = 2.55 s. = Rise time. Tf = Tr = 2.55 s. = Fall time. Tr+Tf = 2.55 + 2.55 = 5.10 s. = Time to hit gnd. Ball #2: h = 0.5g*t^2 = 20.0 m. 4.9*t^2 = 20 t^2 = 4.08 Tf = 2.02 s. = Fall time = time to hit gnd. b. Ball #1...
*October 29, 2014*

**phy**

Fs = m*g = 72.7kg * 9.8N/kg = 712.5 N. = Force of the student. P = F * d/t = 712.5 * 11.9/10.1 = 839.4 J./s = 839.4 Watts = 0.8394 Kilowatts.
*October 29, 2014*

**Physics**

Vo = 60km/h = 60,000m/3600s = 16.67 m/s. V = 15km/h = 15,000m/3600s = 4.17 m/s. a = (V^2-Vo^2)/2d = (4.17^2-(16.67^2))/900 = -0.289 m/s^2. d = (Vf^2-Vo^2)/2a d = (0-(16.67^2)/-0.579 = 480 m. To stop. 480-450 = 30 m. Further before coming to rest.
*October 28, 2014*

**Physics**

I believe there is an error in the problem. The problem should read: The speed of a train is reduced from 60km/h to 15km/h(for example) at the same time as it travels a distance of 450 m. If the retardation is uniform, find how much further it will travel before coming to rest...
*October 28, 2014*

**Physics**

V = I*R = 0.0015A * 20 = 0.03 Volts.
*October 28, 2014*

**Physics**

See previous post: Tue, 10-28-14, 12:16 AM.
*October 28, 2014*

**Math**

V = Vo + g*Tr = 0 @ max Ht. Tr = -Vo/g = -55/-32 = 1.72 s. = Rise time. Tf = Tr = 1.72 s. = Fall time. Tr+Tf = 1.72 + 1.72 = 3.44 s. To hit gnd
*October 28, 2014*

**Math HELP!**

Yes!
*October 28, 2014*

**Math**

(x+72/2)^2 = (x+36)^2 = x^2 + 72x + 1296 k = 1296
*October 28, 2014*

**Physic**

Vo = 26.7 m/s V = 0 u = 0.70 a. u = a/g a = g*u = (-9.8) * 0.70 = -6.86 m/s^2. V^2 = Vo^2 + 2a*d = 0 @ max distance. d = -(Vo^2)/2a = -(26.7^2)/-13.72 = 52 m
*October 28, 2014*

**Physics**

u = a/g = 0.8 a = 0.8*g = 0.8 * (-9.8) = -7.84 m/s^2 d = (V^2-Vo^2)/2a = (0-(20^2)/-15.68 = 25.5 m. To stop. 75-25.5 = 49.5 m. from deer.
*October 28, 2014*

**Physics**

See previous post.
*October 28, 2014*

**Physics**

Fb = m*g = 3kg * 9.8N/kg = 29.4 N. = Force of the brick. Fp = 29.4*sin34 = 16.44 N. = Force parallel to the incline. d = (16.44/120) * 1m = 0.137 m.
*October 28, 2014*

**Physics**

a. Work = F*d = 80 * 5 = 400 J. b. h = 5*sin29 = 2.424 m. Work = F*h = mg*h = 98*2.424 = 237.6 J. c. Work = 20 * 5 = 100 J.
*October 27, 2014*

**physics**

You haven't given all of the INFO: 1. Is the skier coasting down hill? 2. Is she being pulled up hill at constant speed?
*October 27, 2014*

**Physics**

h = 11.2km = 11,200 m. h = 0.5g*t^2 = 11,200 4.9*t^2 = 11,200 t^2 = 2286 Tf = 47.8 s. = Fall time.
*October 27, 2014*

**Pre-Algebra**

2. X Tubas. 2x Trombones. 4x Trumpets. X = 2 Tubas 2x = 2 * 2 = 4 Trombones. 4x = 4 * 2 = 8 Trumpets. Total players = 2 + 4 + 8 = 14. 3. Cost = (2.88/2) * 6Dozens = $8.64 for 6 dozens. Profit = Sale price - Cost. 4. From 6:50AM to 10:15AM = 3h and 25 min = 205 Min. 205Min * ...
*October 27, 2014*

**science**

P^2 = 4*pi^2(L/g) Since g is in the denominator, a smaller g means a longer period or lower frequency(1/P). Therefore, the clock will run slower on the moon.
*October 27, 2014*

**physics**

Fw = m*g = 35.2 * 9.8 = 345 N. = Force of the wagon. Fp = 345*sin18.3 = 108.3 N. = Force parallel to the hill. a = (Fex-Fp)/m = (125-108)/35.2 = 0.474 m/s^2. V^2 = Vo^2 + 2a*d = 0 + 0.949*75.4 = 71.54 V = 8.46 m/s.
*October 27, 2014*

**physics**

h = 1.150 m. Dx = 0.410 m. a. h = 0.5g*t^2 = 1.150 4.9*t^2 = 1.150 t^2 = 0.235 Tf = 0.484 s. = Fall time. b. Dx = Xo*Tf = 0.410 m. Xo * 0.484 = 0.410 Xo = 0.846 m/s. = Speed across table.
*October 27, 2014*

**Physics**

a = 0.0235 m/s^2. t = 67.8 s. d = 1km = 1,000 m. d = Vo*t + 0.5a*t^2 = 1,000 m. Vo*67.8 + 0.5*0.0235*67.8^2 = 1000 67.8Vo + 54 = 1000 67.8Vo = 1000-54 = 945.99 Vo = 14 m/s.
*October 27, 2014*

**Physics**

Vo = 3.01 m/s. t = 3.89 s. a = 3.63 m/s^2. V = Vo + a*t. Solve for V.
*October 27, 2014*

**Physics**

Energy = KE2-KE1 = 0.5m*V2^2-0.5m*V1^2 = 800*40^2 - 800*15^2 = 1,100,000 J.
*October 27, 2014*

**physics**

a = 3.7 m/s^2. d = 67 m. Vo = 0 V = ? t = ? a. V^2 = Vo^2 + 2a*d. Solve for V. b. d = 0.5a*t^2 = 67 m. Solve for t.
*October 27, 2014*

**physics**

Incomplete.
*October 27, 2014*

**physics**

Vo = 17.9 m/s. V = 31.8 m/s. d = 188 m. V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d = (31,8^2-17.9^2)/376 = 1.84 m/s^2.
*October 27, 2014*

**Science Physics**

V^2 = Vo^2 + 2g*h = 0 + 19.6*1.75 = 34.3 V = 5.86 m/s. Note: Always show your Eq before plugging in the values.
*October 27, 2014*

**physics intro**

V^2 = Vo^2 + 2g*h = 0 @ max ht. h = -(Vo^2)/2g = -(75^2)/-64 = 87.9 Ft.
*October 27, 2014*

**Physics**

See previous post: Mon, 10-27-14, 2:13 PM.
*October 27, 2014*

**physics**

Work = Fap*Cos A * d = 555 J. Fap*Cos36 * 15 = 555 12.14*Fap = 555 Fap = 45.7 N. = Force applied. = Tension in the strap.
*October 27, 2014*

**physics**

Fap-Fk = m*a = m*0 = 0 Fk = Fap = 62.9 N. = Force of kinetic friction.
*October 27, 2014*

**physics**

F = 1.35 N. a = 1.5 m/s^2 F = m*a m = F/a
*October 27, 2014*

**Physical Science**

m1 = 0.16 kg m2 = 80kg V1 = 28 m/s. (m1+m2)*V = m1*V1 (0.16+80)V = 0.16*28 V = 4.48/(0.16+80) = 0.056 m/s.
*October 27, 2014*

**Physics**

a = F/m = (5.5-2.5)/15 = 0.20 m/s^2. V = Vo + a*t = 0 + 0.2*4 = 0.8 m/s.
*October 26, 2014*

**Physics**

uk = a/g = 0.1372 a = 0.1372 * g = 0.1372 * (-9.8) =-1.34 m/s^2. V^2 = Vo^2 + 2a*d = 0 @ max. ht. d = -(Vo^2)/2a = -(16.8^2)/-1.34 = 210 m
*October 26, 2014*

**Physics**

h = 17.6 m. g = 9.8 m/s^2 h = 0.5g*t^2 = 17.6 m Solve for t.
*October 26, 2014*

**algebra**

a. $30/4gueest = $7.5 per guest Y = 7.5x b. Slope = 7.5 c. Y = 7.5x = 7.5 * 10 = $75 (x, y) = (10,75). (2,15), (4,30), (0,0).
*October 26, 2014*

**physics**

X = m1*V1 = 2165 * 17 = 36,805 Y = m2*V2 = 1300 * 27 = 35,100 Tan A = Y/X = 35,100/36,805 = 0.95367 A = 43.64o m*V = X/Cos A = 36,805/Cos43.64 = 50,859 (m1+m2)V = 50,859 (2165+1300)V = 50,859 V = 50,859/(2165+1300) = 14.7 m/s. @ 43.64o
*October 26, 2014*

**physics**

Vo = 100km/h = 100,000m/3600s. = 27.8 m/s. a = F/m = -4800/730 = -6.58 m/s^2. V = Vo + a*t = 27.8 - 6.58*1.9 = 15.3 m/s. Momentum = m*V = 730 * 15.3 = 11,174
*October 26, 2014*

**Math**

P = Po + Po*r*t P = 3,000 + 3000*(0.10/12)*3 = $3,075.
*October 26, 2014*

**physics**

Vo = 20 m/s[0o] V = 20 m/s[30o] a = (V-Vo)/t = (20[30o]-20[0o])/5 = (20*cos30+i20*sin30-20)/5 = (17.32+10i-20)/5 = (-2.68+10i)/5 = -0.536 + 2i,(Q2). Tan Ar = Y/X = 2/-0.536 = -3.73134 Ar = -75o = Reference angle. A = -75 + 180 = 105o,CCW = 15o W. of N. a = 2/sin105 = 2.07 m/s^...
*October 26, 2014*

**Power Transmission**

rpm = (24/60) * 120rpm = 48.
*October 25, 2014*

**Physics**

Xo = 15 m/s. h = 90 m. g = 9.8 m/s^2 a. h = 0.5g*t^2 = 90 m. Solve for t. b. Dx = Xo * t
*October 25, 2014*

**physics**

Vo = 50km/h = 50,000m/3600s = 13.89 m/s. a = (V-Vo)/t = (0-13.89)/5 = -2.78 m/s^2 F = m*a = 1000 * (-2.78) = -2780 N. The negative sign means the force is against the motion.
*October 25, 2014*

**Calculus/pre-trig**

D = B^2 - 4AC 1. If B^2 is less than 4AC(B^2 < 4AC), the Determinant is negative and we have 2 imaginary solutions and no real solutions. 2. If B^2 = 4AC, we have one real solution and no imaginary solutions. 3.If B^2 > 4AC, we have 2 real solutions and no imaginary ...
*October 25, 2014*

**Physics**

Fb = m*g = 11.2kg * 9.8N/kg = 109.8 N. = Force of block. Fp = 109.8*sin24 = 44.64 N. = Force parallel to the incline. d = (1m/31,300N) * Fp d = (1m/31,300N) * 44.64N = 0.0014262 m. = 0.143 cm.
*October 25, 2014*

**physics**

Xo = 13 m/s. Dx = 60 m. h = ? Dx = Xo * Tf = 60 Tf = 60/Xo = 60/13 = 4.62 s. = Fall time. h = 0.5g*Tf^2 = 4.9*4.62^2 = 105 m.
*October 25, 2014*

**intermidiate algebra**

Eq1: 3x + 300y = 111 Eq2: 5x + 600y = 198 Multiply Eq1 by -5 and Eq2 by 3 : -15x - 1500y = -555 +15x + 1800y = +594 Sum: 300y = 39 Y = $0.13 per mile. In Eq1, replace Y with 0.13 and solve for X: 3x + 300*0.13 = 111 3x = 111 - 39 = 72 X = $24 per day.
*October 25, 2014*

**physis**

W = 750N/6 = 125 N. on the moon.
*October 24, 2014*

**Math, Trig/Pre Calc**

See previous post: Fri, 10-24-14, 5:38 PM.
*October 24, 2014*

**Pre-Calc/Trig...**

Y = x^2 - 2x - 3 Vertex Form: Y = a(x-h)^2 + k h = -b/2a = 2/2 = 1 K = 1^2 - 2*1 - 3 = -4 Vertex Form: Y = 1(x-1)^2 - 4 Y = x^2 - 2x - 3 = 0 -3 = 1*(-3). Sum = 1 + (-3) = -2 = b. Factored or Intercept form:(x+1)(x-3) = 0
*October 24, 2014*

**math**

Tan13 = h/200 h = 200*Tan13 = 46 Ft. Cos13 = 200/r r = 200/Cos13 = 205 Ft = hypotenuse.
*October 24, 2014*

**Math 222**

1. g^2 - 6g - 55 = 0 -55 = 1*(-55) = 5*(-11) Choose the pair of factors whose sum = B : 5, and -11. (g+5)(g-11) = 0 g+5 = 0 g = -5. g-11 = 0 g = 11. Solution: g = -5, and 11. 2. k^3 + k = 0 k(k^2+1) = 0 k = 0 k^2 + 1 = 0 k^2 = -1 k = sqrt(-1) = I Solution: k = 0, and i. 3. k^2...
*October 23, 2014*

**Algebra**

Cannot be factored. Use Quadratic Formula and get: X1 = -737.1. X2 = 122.1.
*October 23, 2014*

**Physics**

Vo = 1560 m/s @ 67.4o Range = Vo^2*sin(2A)/g = 1560^2*sin(134.8)/9.8 = 176,205 m. Range = Vo*cos67.4*T = 176,205 T = 176,205/1560*cos67.4 = 294 s. in flight.
*October 23, 2014*

**math**

d = 110 - 30t = 40. Solve for t.
*October 23, 2014*

**physics**

Vo = 12.8 m/s @ 33.5o Yo = 12.8*sin33.5 = 7.06 m/s. Tr = -(Yo)/g = -7.06/-9.8 = 0.721 s. = Rise time. Tf1 = Tr = 0.721 s. = Fall time from max ht. to top of building. Tr+Tf1+Tf2 = 3.4 s. 0.721 + 0.721 + Tf2 = 3.4 Tf2 = 3.4 - 1.44 = 1.96 s. = Fall time from top of building to ...
*October 23, 2014*

**physics**

West = 340*Cos20 = 319.5 km. North = 340*sin20 = 116.3 km.
*October 23, 2014*

**accounting**

Po = $9800, r = 0.02, t = 15yrs. I = Po*r*t
*October 23, 2014*