Friday
August 22, 2014

Posts by henry


Total # Posts: 8,923

math
Specific Gravity
August 21, 2014

Math
N = The number. N + 0.2N = 28 1.2N = 28 N = 28/1.2 = 28/(1 1/5) = 28/(6/5) = 28 * 5/6 = 140/6 = 70/3.
August 21, 2014

Algebra
Velocity = 4.5 Ft/s. Downward. Speed = 4.5 Ft/s.
August 21, 2014

physics
distance = 4 + 2 + 4 + 2 = 12 m. Displacement = Df-Do = 0-0 = 0. Df = Final distance. Do = Starting point.
August 21, 2014

physics
Distance = 5 + 3 = 8 km. Displacement = 5-3 = 2 km.
August 21, 2014

physics
Vr = 186m[23o] + 327m[133o] X = 186*cos23 + 327*cos133 = -51.8 m/s. Y = 186*sin23 + 327*sin133 = 311.8 m/s. Tan Ar = Y/X = 311.8/-51.8 = -6.01986 Ar = -80.6o = Reference angle. A = -80.6 + 180 = 99.4o CCW = 9.4o W of N. Vr = Y/sin A = 311.8/sin99.4)=316 m/s [99.4o] = 316 m/s[9...
August 21, 2014

physics
Vs = 3.12 - 1.35 = 1.77 m/s.
August 21, 2014

Physics
Vo = 25m/s[30o] Vx = 25*cos30 = 21.65 m/s. Vy = 25*sin30 = 12.50 m/s. h=(V^2-Vy^2)/2g=(0-(12.5^2)/-19.6=7.97 m Range = Vo^2*sin(2A)/g Range = 25^2*sin(60)/9.8 = 55.23 m. V=Vy + g*t = 12.50 + (-9.8*2) = -7.1m/s 21.65 - 7.1i=22.78m/s[-18.16o]=Velocity 2 seconds after the launch...
August 19, 2014

physics
Cannot solve without graphs.
August 19, 2014

Physics
a. X = 30km/h Y = 40km/h Tan A = Y/X = 40/30 = 1.33333 A = 53.13o E. of N. if wind is coming from the West. = 53.13o W. of N. if wind is coming from the East. V = Y/sin A=40/sin53.13=50 km/h[53.13o]
August 19, 2014

math
Thanks! I thought it was 30o from the x axis, because the problem didn't say 30o East of North.
August 18, 2014

math
D = 90km[30o] + 150km[0o] X = 90*Cos30 + 150 = 228 km. Y = 90*sin30 = 45 km. Tan A = Y/X = 45/228 = 0.19742 A = 11.17o D=X/CosA = 228/Cos11.17=232 km[11.17o] Dx = 232*cos11.17 = 227.998 km East of starting point.
August 18, 2014

math
5*15 + 2 = 77 6*15 + 2 = 92
August 18, 2014

math
d = 1in/Xmi. * M mi = M/X inches.
August 18, 2014

math
P = Po + 0.5Po = $81. 1.5Po = 81 Po = $54 = Initial price or Cost.
August 18, 2014

geometry
9<n<14 Values of n: 10, 11, 12, 13. Sum = 10+11+12+13 = 46 cm. 5<n<9 Values of n: 6, 7, 8. Sum = 6+7+8 = 21 cm. n = 5 cm(Isosceles Triangle). n = 9 cm(Isosceles Triangle). Sum Total=5+6+7+8+9+10+11+12+13 = 81 cm.
August 17, 2014

mat
6.5Ft/3in = 2.17Ft/in Depth = 5 + 2.17x X = The # of inches of rain.
August 17, 2014

Physics
Yes, I'm glad it didn't fall on MY head!
August 17, 2014

Physics
Mass = 20kg?(Check for error). a = g = 9.8 m/s^2 F = m * g
August 17, 2014

physics
Vo = 84m/s[45o]. Dx = Vo^2*sin(2A)/g=84^2*sin90/9.8=720 m with zero wind. (720-630)/720 * 100% = 12.5% Decrease.
August 17, 2014

math
d^2 = X^2 + Y^2 = 4^2 + 5^2 = 41 d = 6.4 km. = Shortest distance to his home.
August 17, 2014

Geometry
One side = L units. 2nd side = 3L units. 3rd side = 15 units. 3L < 15 L < 5 L = 4 = Largest possible integer. 3L = 3*4 = 12. P = 4 + 12 + 15 = 31 = Max. possible perimeter.
August 15, 2014

trig
Angular velocity is usually given in rad/s., deg./s, or rev/min. So please check your INFO.
August 15, 2014

Trigonometry
12.4rev/ride * 3rides = 37.2 Revs. A = 37.2rev * 360Deg/rev = 13,392o = 233.6 Radians. Circumference=pi*2r = 3.14*36.6=114.92 m. d = 37.2rev * 114.92m/rev = 4275.2 m. traveled.
August 15, 2014

Physics
Vo = 36km/h = 36,000m/3600s = 10 m/s. V = 9km/h = 9000m/3600s = 2.5 m/s. a = (V^2-Vo^2)/2d a = (2.5^2-10^2)/300 = -0.3125 m/s^2. d = (V^2-Vo^2)/2a d = (0-2.5^2)/-0.6250 = 10 m. Further.
August 15, 2014

physics
a=(V^2-Vo^2)/2d=(0-(20^2))/30=-13.3m/s^2
August 14, 2014

High School Physics
X = 10 m/s Y = 20 m/s V^2 = X^2 + Y^2 V^2 = 10^2 + 20^2 = 500 V = 22.4 m/s = Resultant velocity. a = (V-Vo)/t = (22.4-0)/t = 22.4/t m/s^2 d = 0.5*a*t^2 = 150 0.5*(22.4/t)*t^2 = 150 m (11.2/t)*t^2 = 150 11.2t = 150 t = 13.4 s.
August 12, 2014

Math
C = 75 + 5f. C is the dependent variable. It depends on the value of f.
August 12, 2014

pHYSICS`
m*g = 50kg * 9.8N/kg = 490 N. = Wt. of cart. Fk = u*mg = 0.2 * 490 = 98 N. = Force of kinetic friction. a=(V-Vo)/t = (0.90-0)/2.8 = 0.321 m/s^2/ F-Fk = m*a F - 98 = 50*0.321 = 16.07 F = 16.07+98 = 114.1 N.
August 11, 2014

physics
T = 50min * 1h/60min = 5/6 h. T = t1 + t2 = 5/6 h. d/(Vb-Vs) + d/(Vb+Vs) = T 8/(Vb-2.8) + 8/(Vb+2.8) = 5/6 LCD = (Vb-2.8)(Vb+2.8). (8(Vb+2.8)+8(Vb-2.8))/(Vb-2.8)(Vb+2.8)= 5/6. (8Vb+22.4+8Vb-22.4)/(Vb-2.8)(Vb+2.8)=5/6 16Vb/(Vb-2.8)(Vb+2.8) = 5/6 Cross multiply: 96Vb = 5(Vb-2.8...
August 10, 2014

Math
Eq1: 2r - 7s = -6 Eq2: 7r - 2s = 32 Multiply Eq1 by (-7) and Eq2 by 2; then add: -14r + 49s = 42 +14r - 4s = 64 Sum: 45s = 106 S = 2 16/45 = 106/45. In Eq1, replace s with 106/45: 2r - 7*(106/45) = -6 2r - 742/45 = -6 Multiply by 45: 90r - 742 = -270 90r = -270 + 742 = 472 r...
August 10, 2014

Algebra
15x(x+2) + 1(x+2) Factor out x+2: (x+2)(15x+1) = Final answer.
August 10, 2014

physics
a = (V-Vo)/t = (-4.4-6)/0.04=-260 m/s^2.
August 10, 2014

physics
I=(V1-V2)/(R1+R2) = (12-8)/(15+1)=
August 10, 2014

PHYSICS
d = 0.5a*t^2 = 10 m. 0.5a*(5.5)^2 = 10 15.125a = 10 a = 0.661 m/s^2. V = a*t = 0.661 * 5.5 = 3.636 m/s. d = Vo*t - o.5a*t^2 d=3.636*5.10 - 0.5*0.661*5.10^2=9.95 m.
August 10, 2014

physics
h = (V^2-Vo^2)/2g h = (0-(10^2)/-20 = 5.0 m.
August 10, 2014

Alegbra
a. (42,900-5100)/60 = b. Po = 42900 - 5100 = $37,800. P = Po*r*t/(1-(1+r)^-t) r = (2.5%/12)/100* = 0.00208 = Monthly % rate expressed as a decimal. t = 60 Months. P = (37,800*0.00208*60)/(1-1.00208^-60) = $40,251.02 Monthly Payments = P/t
August 10, 2014

physics
Vo = a*t = 17m/s^2 * 20s = 340 m/s. h1 = 0.5a*t^2 = 0.5*17*20^2 = 3400 m. = Ht. at which the engine shuts off. hmax = h1 + (V^2-Vo^2)/2g. hnax = 3400 + (0-(340^2)/-19.6 =9298 m. = 9.298 km above gnd. The rocket did not reach the required 12 km.
August 9, 2014

physics
T = 7days/week * 24h/day = 168 h. 0.2kW * 168h = 33.6 kWh Used. Cost = $0.14/kWh * 33.6kWh = $4.70
August 9, 2014

physics
D = Vo*t + 0.5a*t^2 D = 2*10 + 0.5*0.2*10^2 = 30 m.
August 9, 2014

math
B = # of boys in camp. 0.3B = # of boys from N.Y.S. 0.2 * 0.3B = 0.06B=# of boys from N.Y.C. (0.06B/B)*100% = 6% = Percentage of boys in camp from N.Y.C.
August 8, 2014

math
A = C pi*r^2 = pi*D pi*r^2 = pi*2r Divide both sides by pi*r r = 2 Inches. D = 2r = 2 * 2 = 4 Inches.
August 8, 2014

Physics
a. h = 12*s1n30 = 6 m. V^2 = Vo + 2g*h = 0 + 19.6*6 = 117.6 V = 10.84 m/s. b. m*g=83kg * 9.8N/kg = 813.4 N.=Wt. of the child. Fn = mg*cos30 = 813.4*cos30 = 704.4 N. = Normal = Force perpendicular to the slide. Fk = u*Fn = 0.30 * 704.4 = 211.3 N. = Force of kinetic friction. ...
August 8, 2014

Physics
d2 = d1+29 Vo2*t + 0.5a*t^2 = Vo1*t + 29 m 42t + 1.5t^2 = 28t + 29 1.5t^2 + 42t - 28t = 29 1,5t^2 + 14t = 29 1.5t^2 + 14t - 29 = 0 Use Quadratic Formula and get: t = 1.745 s. To pass the train. V = Vo + a*t = 42 + 3*1.745 = 47.24 m/s.
August 8, 2014

Math 221
See previous post: Thu, 8-7-14, 11:29PM.
August 8, 2014

Math 221
AC Method: 1. 2a^2 * 3a + 1 A*C = 2*1 = 2. 2+1 = 3 = B 2a^2 + (2a+a) + 1 Form 2 Binomials and factor: (2a^2+2a) + (a+1) 2a(a+1) + (a+1) (a+1)(2a+1). 2. 15x^2 + 31x + 2 A*C = 15*2 = 30 = 30*1. Sum = (30+1)=B. 15x^2 + (30x+x) + 2 (15x^2+30x) + (x+2) 15x(x+2) + (x+2) (x+2)(15x+1...
August 7, 2014

algebra
b = p-a-c
August 7, 2014

math
Shortest side = X. Other side = 2X. x + 2x > 11 3x > 11 X > 11/3 X > 3 2/3 X = 4 = Shortest possible length. 2X > 22/3 2X > 7 1/3 2X = 8.
August 7, 2014

math
Y yards * (3/8)jumps/yard = 3Y/8 Jumps.
August 7, 2014

Physics
Average Speed = (40+60)/2 = 50 km/h
August 7, 2014

trigonometry
X = 4 Ft/s Y = -2km/h = -2000m/3600s * 3.3Ft/m = -1.833 Ft/s Tan A = Y/X = -1.833/4 = -0.45825 A = -24.62o = 24.62o South of East. = 65.38o East of South = Direction. Magnitude = X/Cos A = 4/Cos(-24.62) = 4.4 Ft/s.
August 7, 2014

trigonometry
m*g = 200,000N. Fp = mg*sin A = 200,000*sin28 = 98,894 N = Force parallel with the incline = The pull on the rope.
August 7, 2014

Physics
Circumference=pi * 2r = 3.14 * 3=9.42 m. d = 0.5a*t^2 = 9.42 0.5*2.3*t^2 = 9.42 1.15t^2 = 9.42 t^2 = 8.19 t = 2.86 s.
August 6, 2014

math
3. Discount=((10.80-9.18)/10.80)*100%=15%. 4. Tax = (3.20/100)*Va = $1952 Solve for Va(assessed value). 7. Loan Amount = 7250-3000 = $4250 Cost = 7250 + 4250*(0.125/12)*9 = 8. Same procedure as #3. 9. Rate = ((4250-3910)/4250)*100% =
August 6, 2014

algebra
post it.
August 4, 2014

Physics
The horizontal component does not change
August 3, 2014

Math
h = 164t - 16t^2 = 400 Ft. -16t^2 + 164t = 400 -16t^2 + 164 - 400 = 0 Use Quadratic Formula and get: t = 4, and 6.25 seconds. Answer = 4 s. The rocket is falling when t = 6.25 s.
August 2, 2014

physics
10^-7J = 1 erg Multiply both sides by 10^7: 10^0J = 10^7 erg 1 J. = 10^7 erg.
August 1, 2014

science
Fr = 20N[270o] + 40N[45o] + 10[0o] = -20i + 40*cs45) + i40*sin45) + 10 = -20i + 28.28 + 28.28i + 10=38.28 + 8.28i Fr^2 = 38.28^2 + 8.28^2 = 1533.9 Fr = 39 N.
July 31, 2014

physics
a = (V-Vo)/t = (21.5-12.7)/3.45 =
July 31, 2014

PHYSICS
V = 300rev/min * 6.28rad/rev * 1min/60s = 31.4 rad/s. Circumference = pi*2r = 3.14 * 10=31.4 m. V = 300rev/min * 31.4m/rev * 1min/60s = 157 m/s. = Linear speed.
July 30, 2014

physics
F = m*a a = F/m = 3.0*10^4/0.06 = 5*10^5 m/s^2. a = (V-Vo)/t = 5*10^5 m/s^2 (75-0)/t = 5*10^5 5*10^5t = 75 t = 1.5*10^-4 s.
July 30, 2014

physics
m*g = 50kg * 9.8N./kg = 490 N. = Wt. of the box. Fp = 490*sin30 = 245 N. = Force parallel to the incine. Fn = 490*cos30 = 424.4 N. = Force perpendicular to the incline. Fk = u*Fn = 0.1 * 424.4 = 42.44 N. = Force of kinetic friction. At bottom of incline: KE + PE = mg*h - Fk*L ...
July 30, 2014

Physics
h = 32 m. A = 24.25o B = 18.2o Tan24.25 = h/X1 = 32/X1 X1*Tan24.25 = 32 X1 = 32/Tan24.25 = 71 m.=Hor. distance between boat A and the cliff. Tan18.2 = h/(X1+X2) = 32/(71+X2) (71+X2)*Tan18.2 = 32 71+X2 = 32/Tan18.2 = 97.33 X2 = 97.33-71 = 26.3 m=Distance between boat A and B.
July 30, 2014

Physics
m*g = 68kg * 9.8N./kg = 666.4 N. = Wt. of skier. Fp = 666.4*sin32 = 353.1 N. = Force parallel with incline. Fn = 666.4*cos32 = 565.1 N. = Normal = Force perpendicular to the incline. Fk = u*Fn = 0.05 * 565.1 = 28.26 N. = Force of kinetic friction. Fp-Fk = m*a a=(Fp-Fk)/m =(353...
July 30, 2014

math
12x = 3x+150 + 300 12x - 3x = 450 9x = 450 X = 50 Shirts.
July 29, 2014

physics
a = (V^2-(Vo^2))/2d =(0-(22^2))/8 = -60.5m/s^2. a = (V-Vo)/t t = (V-Vo)/a = (0-22)/-60.5 = 0.364 s.
July 29, 2014

Physics
The resistance of the voltmeter should be large compared to the resistance across which the voltage is being measured. If not, the voltmeter will act as an addition load on the circuit resulting in a lower reading. The voltmeter should be connected in parallel with the ...
July 29, 2014

electric circuit
Fuses are always connected in series with the circuit. Therefore, its' resistance should be small compared to the resistance of the circuit. The circuit of an Ammeter has a much lower resistance than a Voltmeter. So the fuse in the Ammeter has a higher current rating. ...
July 29, 2014

physics
1. 60s. * 1Wave/0.27s. = 222 Waves.
July 28, 2014

PHYSICS
V = Vo + a*t = 4.50 m/s. Vo + (-2.7)*3 = 4.5 Vo = 4.5 + 8.1 = 12.6 m/s. D = Vo*t + 0.5a*t^2 D = 12.6*3 - 0.5*2.7*3^2 = 25.7 m.
July 28, 2014

Physics 2
1. The step-down transformer reduces the primary voltage by a factor equal to the turns ratio. For instance, if the turns ratio was 4:1, the voltage across the secondary would be 1/4 of the primary voltage. In a step-up transformer with a turns-ratio of 1:4, the voltage across...
July 28, 2014

physics
d1 = d2 + 100m. 60t = 40t + 100 60t-40t = 100 20t = 100 t = 5 Hours.
July 27, 2014

math
Y > 8-5 Y > 3
July 27, 2014

finance
Program A: (5000/100,000)*100 = 5%Profit. Program B: (10,000/220,000)*100 = 4.55% Profit.
July 27, 2014

Physics 2
L = 1 mm to 1m. L = V/F F = V/L = 3*10^8/1*10^-3m = 3*10^11 Hz. F = 3*10^8/1m = 3*10^8 Hz.
July 27, 2014

Physics 2
L = V/F F = V/L = 300*10^6/300 = 10^6 Hz = 1 mHz
July 27, 2014

physics
A. Np/Ns = Vp/Vs = 120/12 = 10/1. Turns Ratio = 10:1 Ts = Tp/10 To find the number of turns on the secondary(Ts), we need to know the number of turns on the primary(Tp). B. 120 * I = 6 W. Solve for I. Fr = 1/(2pi*Sqrt(LC) Fr = 1(6.28*Sqrt( 0.40*30*10^-9) = 8.33 Million Hertz...
July 27, 2014

science
d = (V^2-Vo^2)/2a=(0-(20^2)/-8.6=46.51 m = Stopping distance. d = 55+22+5 = 82 m. = Distance through intersection. d = Vo*t + 0.5a*t^2 = 20*(3-0.25) + 0.5*2*(3-0.25)^2=62.6 m. Therefore, the driver must step on the brakes; because he or she cannot drive the required 82 meters ...
July 27, 2014

physics
Wt. of Cart=m*g = 250kg * 9.8N/kg=2450 N Fp = 2450*sin50 = 1877 N. = Force Parallel to the incline. Fn = 2450*cos50 = 1575 N. = Normal force Fk = u*Fn = 0.22 * 1575 = 346.5 N. = Force of kinetic friction. Fe-Fp-Fk = m*a Fe-1877-346.5 = m*0 = 0 Fe-2223 = 0 Fe = 2223 N. = Force ...
July 27, 2014

trigonometry
Smaller Pulley: V=15rev/12s * 6.28rad/rev = 7.85 rad/s Larger Pulley: V = (6cm/20cm) * 7.85 = 2.36 rad/s.
July 26, 2014

physic
da = 0.5g*t^2 = 4.9*2^2=19.6 m. in 2 s. Va = Vo + g*t = 0 + 9.8*2 = 19.6 m/s in 2 s. Da = Db - 19.6 19.6t + 4.9t^2 = 30t + 4.9t^2 - 19.6 19.6t - 30t + 4.9t^2 - 4.9t^2 = -19.6 -10.4t = -19.6 t = 1.88 s. to reach gnd. h = 30t + 4.9t^2 = 30*1.88 + 4.9*1.88^2 = 73.9 m.
July 25, 2014

PHYSICS
Circumference=pi*2r = 3.14 * 20=62.83 m. d = (270o/360o) * 62.83m = 47.12 m. = Distance traveled. d = r*t = 47.12 m. r = 47.12/t = 47.12/20 = 2.36 m/s=Speed. Displacement = 10m[270] - 10[0o] -10 - 10i = -14.14m.[45o] = 14.14m[-45o]
July 23, 2014

Math
1344 = 1*1344 = 1*2*672 = 1*2*3*224 = 1*2*3*4*56 = 1*2*3*4*7*8. 1440 = 1*1440 = 1*2*720 = 1*2*3*240 = 1*2*3*4*60 = 1*2*3*4*5*12=1*2*3*4*5*6*2 2160 = 1*2160 = 1*2*1080 = 1*2*3*360 = 1*2*3*4*90 = 1*2*3*4*5*18=1*2*3*4*5*6*3 GCF = 4. 2. Income = $X. (1/10+1/3+1/5)X + 1320 = X (3/...
July 22, 2014

Math
1. 40%/100% = 40/100 = 2/5. 2. The largest side should be less than the sum of the two smaller sides: 9cm, 16cm, and 8cm. 16 < 9 + 8.
July 22, 2014

algebra
6x - (2/5) 6*0 - (2/5) = -2/5 6*1 - (2/5)=6/1 - 2/5 = 30/5 - 2/5=28/5. 6*2 - 2/5 = 12/1 - 2/5 = 60/5 - 2/5=58/5 (6x-2)/5 (6*0-2)/5 = -2/5 (6*1-2)/5 = 4/5 (6*2-2)/5 = 10/5 = 2.
July 22, 2014

Math
D. A,C,B,D.
July 22, 2014

Math 221
2 < Y <= 7.
July 20, 2014

mat/117
F(x) = -3x^2 + 3x + 9 = 0 Divide by -3: x^2 - x - 3 = 0 Use Quadratic Formula and get: X = 2.30, and -1.30 = Approx. 2, and 3.
July 20, 2014

physics
3[90o] + (-4) + F = 0 3i + (-4) + F = 0 F = 4 - 3i = 5N[-37o] = 5N[37o] S. of E. =5N[53o] E. of S.
July 20, 2014

math
X oz. of black beans. (X+180) oz. of red beans. Total = X + (X+180) = 2x + 180. X/(2x+180) = 0.20 x = 0.4x + 36 0.6x = 36 X = 60 Oz. of Black beans. X+180 = 60+180 = 240 Oz. of red beans. Total = 60 + 240 = 300 oz. of beans. 0.3 * 300 = 90 oz. of mixed beans.
July 17, 2014

math
We need the height. A = 2*W*h + 2*L*h A = 2*6*h + 2*9*h
July 16, 2014

math
A = 2.60*r^2 = 2.60 * 5^2 = 65 Ft.^2
July 16, 2014

trig
X = 60 Ft. = Run Y = Rise A = 21o Tan 21 = Y/X = Y/60 Y = 60*Tan 21 = 23.0 Ft. = Rise
July 16, 2014

physics
Ma*V = 1500*25 = 37,500 = Momentum of Boxcar A. (Ma+Mb)*V = 37,500 (1500+2000)V = 37,500 3500V = 37,500 V = 10.71 m/s.
July 14, 2014

physics
r = 60km/h = 60,000m/3600s. = 16.67 m/s. d = d1 + d2 d1 = r*t = 16.67m/s * 1s = 16.7 m. d2 = (V^2-Vo^2)/2a d2 = (0-(16.7)^2/-6 = 46.3 m. d = 16.7 + 46.3 = 63.0 m.
July 12, 2014

electric circuit
We can build 3 12V batteries: 36/12 = 3. We can connect them in parallel to make a 12V-4.5A battery: I = 3 * 1.5 = 4.5A. P = V*I = 12 * 4.5 = 54 Watts.
July 12, 2014

finance
Amount = -12-145+3.50+80 = -$73.50
July 11, 2014

PHYSICS
The given numbers doesn't make sense; please double check the numbers and show all units.
July 11, 2014

PHYSICS
m*g = 2kg * 9.8N/kg = 19.6 N. = Wt. of object being pushed. Fp = 19.6*sin50 = 15.0 N. = Force parallel to the incline. Fn = 19.6*cos50 = 12.6 N. = Normal = Force perpendicular to the incline. Fk = u*Fn = 0.40 * 12.6 = 5.0 N. = Force of kinetic friction. a=(Fap-Fp-Fk)/m = (50-...
July 11, 2014

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