Saturday
November 22, 2014

Posts by Henry


Total # Posts: 9,575

physics
False. The force of kinetic friction is smaller.
November 7, 2014

CAL- derivative
Find the derivative; y= x^3(5x-1)^4 So this is my answer y'=2x(5x-1)^3 + 10x + x(5x-1) Please correct me if my answer is wrong.
November 7, 2014

Algebra
10*Log(2.50*10^5/10^-16) = 10*Log(2.50*10^21) = 214 db.
November 7, 2014

physics
Vo = 1630 m/s[86o] Yo = 1630*sin86 = 1626 m/s. Y = Yo + g*Tr = = 0 @ max Ht. Tr = -Yo/g = -1626/-9.8 = 166 s. = 2.77 Min. Tf = Tr = 2.77 min. = Fall time. Tr + Tf = 2.77 + 2.77 = 5.54 Min. = Time in flight.
November 6, 2014

physics
d = 7.6 m. h = 0.5g*t^2 = 3.3 m. Solve for t. Xo = d/t m/s = Initial Hor. velocity
November 6, 2014

science
a = F/m = 85/5 = 17 m/s^2. V = Vo + a*t = 14 + 17*20 = 354 m/s.
November 6, 2014

math
Tan20 = h/d = 50/d d = 50/Tan20 = 137.4 m.
November 6, 2014

science.
The law of conservation of momentum says it will be the same.
November 6, 2014

physics
V^2 = Vo^2 + 2g*h Vo = 0 2g = 19.6 m/s^2 h = 35 m. Solve for V.
November 6, 2014

Math, Please Help!
X student tickets sold. (723-X) Non-student tickets sold. 3x + 5(723-X) = $2,815. Solve for X.
November 6, 2014

Physics
A. m*g = 19kg * 9.8N/kg = 186.2 N. = Force of the suitcase. u = a/g, a = u*g = 0.54 * 9.8 = 5.29 m/s^2 Fn = mg-F*sin41.3 = 186.2-0.66F = Normal force. F*Cos41.3-.54(186.2-0.66F) = 19*5.29 0.751F - 100.5 + 0.356F = 100.5 1.107F = 201 F = 181.6 N. = Force applied. Fn = 186.2 - 0...
November 6, 2014

nqwiliso s.s.s.
Fr = 30 + 25 + (-40) = 15 N.,Headed East
November 6, 2014

Pre Algebra
Sqrt(25) + (-9) = -4 = A Whole number.
November 6, 2014

physics
(1rev/0.4s) * 60s./min = 150 RPM.
November 6, 2014

physics
F = m*g = 1*9.8 = 9.8 N k = F/d = 9.8N/0.012m = 816.7 N/m.
November 6, 2014

Math
1. Log(9/300) = Log 9 - Log 300 2. Log2(4^2*3^4) = Log2(4^2) + Log2(3^4) = Log2(16) + Log2(81)
November 6, 2014

Science
F1+F2 = m*a = 0.750 * 0.450 = 0.3375 N. Fi-F2 = 0.750 * 0.240 = 0.18 N. Eq1: F1 + F2 = 0.3375 Eq2: F1 - F2 = 0.1800 Sum: 2F1 = 0.5175 F1 = 0.25875 N. In Eq1, replace F1 with 0.25875 0.25875 + F2 = 0.3375 F2 = 0.3375 - -0.25875 = 0.07875 N.
November 6, 2014

physics
See previous post: Thu, 11-7-14, 6:30 AM.
November 6, 2014

physics
See previous post: Thu, 11-7-14, 6:30 AM.
November 6, 2014

physics
d = V*T = 3.50 km T = 3.50/V = 3.50/25 = 0.14 h. T = 3.50/40 = 0.0875 h. 0.14 - 0.0875 = 0.0525 h = 3.15 Min. gained.
November 6, 2014

phisics
Fap = mg*sin45 = 36 N. m = 36/g*sin45 = 5.2 kg Fap = Force applied.
November 6, 2014

algebra
3.65V^2 + 0.0875V^2/0.09 = 62.7 3.65V^2 + 0.9722V^2 = 62.7 4.622V^2 = 62.7 V^2 = 13.56 V = 3.68
November 5, 2014

physics
Fd = (Vs+Vd)/(Vs-Va)*Fa = 1050 Hz. (340+0)/(340-Va) * 980 = 1050 Divide both sides by 980: 340/(340-Va) = 1.0714 364.29-1.0714Va = 340 -1.0714Va = 340-364.29 = -24.29 Va = 22.7 m/s. = Velocity of the ambulance. Vs = Velocity of sound. Vd = Velocity of the detector.
November 5, 2014

algebra
V^2 = Vo^2 + 2g*h = 0 + 64*203 = 12,992 V = 114 Ft/s.
November 5, 2014

Algebra
V = 8*sqrt(h) = 8*sqrt(203) = 114 Ft/s.
November 5, 2014

physics
V^2 = Vo^2 + 2g*h = 0 + 19.6*(10-5) = 98 V = 9.90 m/s @ 5 m above the surface. V^2 = 0 + 19.6*10) = 196 V = 14 m. Just before striking the surface.
November 5, 2014

science
Incomplete.
November 5, 2014

physics
Vo = 10 m/s. V = 5 m/s. d = 150 m. a = ? a. V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d = b. d = (V^2-Vo^2)/2a. V = 0, Vo = 5 m/s.
November 5, 2014

Physics
Incomplete.
November 4, 2014

Algebra
F(x) = Y = -x^2 + 6x + 6 = 0 Use Quadratic Formula. (X, Y) = (-2, 0), (8, 0).
November 4, 2014

Precalculus
Do you mean e^2x - 1 = e^4 or e^(2x-1) = e^4. I will assume the 2nd Eq. (2x-1)*Ln e = 4*Ln e (2x-1)*1 = 4*1 2x-1 = 4 2x = 5 X = 5/2 = 2.5
November 4, 2014

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

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