Monday
July 28, 2014

Posts by henry


Total # Posts: 8,908

maths
See previous post: Tue,8-6-13,12:09 PM

maths
See previous post: 12:09 PM.

maths
Y = 2x Tan A = m1 = 2 A = 63.43o (-1,7/3),(0,2). m2 = Tan B = (2-7/3)/(0+1) = (-1/3)/1 = -1/3. B = -18.43o = -18.43o C = A-B = 63.43 - (-18.43) = 81.9o = Angle between A and B.

Math
What is the question?

maths
CORRECTION: m1 = m2 = -A/B = 6/2 = 3 Y = mx + b = -1 3*3 + b = -1 b = -10 Eq: Y = 3x - 10

maths
(3,-1). -6x + 2y = 1 Parallel lines have equal slopes: m1 = m2 = -A/B = 6/-2 = -3 Y = mx + b = -1 -3*3 + b = -1 b = 8 Eq: Y = -3x + 8

mathematics
P(-6,-2). 3x + 2y = 6 m1 = -A/B = -3/2 m2 = -(-2/3) = 2/3 = Negative reciprocal Y = mx + b = -2 2x/3 + b = -2 (2*-6)/3 + b = -2 -4 + b = -2 b = 2. Eq: Y = 2x/3 + 2

physics
See previous post.

physics
Assuming no wind: Vo*t + 0.5g*t^2 = 1.4 m. 0 + 0.5*1.63*t^2 = 1.4 0.815t^2 = 1.4 t^2 = 1.72 t = 1.31 s.

algebra
Yes, post your problem.

Physics
h1 = Vo*t + 0.5g*t^2 h1 = -9*18 + 4.9*18^2 = 1426 m Above ground when bag was released. h2 = 9*18 = 162 m.. Above point of release. h = 1426 + 162 = 1588 m. Above ground.

physics
A = 3.45 m/s[90o] B = 2.39 m/s[270o] C = V m/s 3.45[90o]+2.39[270]+V = 0 @ the peak of its' trajectory. 3.45*cos90+2.39*cos270+i3.45*sin90+i2.39*sin270 + V = 0 0+0 + 3.45i-2.39i + V = 0 0 + 1.06i + V = 0 V=-1.06i = 1.06 m/s[270o]=1.06m/s[-90o].

math
3X5Y/2Y8 = 15x/16. 15x/16 = 1 = The smallest whole number. 15x = 16 X = 16/15 = 1 1/15. According to my analysis, x cannot equal 0,2,4, nor 6.

science
The current through all elements of a circuit is the same IF there are no elements in parallel.

Physics
tan A = 50m/79m = 0.63291 A = 32.3o East of North = 57.7o CCW. b. Vs = 1.9m/sin57.7 = 2.25 m.[57.7o] = Velocity of swimmer. Vc = 2.25m/s[57.7o] - 1.9[90o] X = 2.25*cos57.7 - 1.9*cos90=1.20 m/s. Y=2.25*sin57.7 - 1.9*sin90 = 0 m/s. b. Vc = 1.20 + i0 = 1.20 m/s =Velocity of the c...

physics
See 6:26 PM post.

physics
See 5:58 PM post.

physics
20*Log(V1/Vo) = 38 db Log(V1/Vo) = 1.9 V1/Vo = 79.4

physics
130db/19 = 6.84 db.

physics
130db/19 = 6.84 db.

physics
a. 10*Log(I1/Io) = 17db Log(I1/Io) = 1.7 I1/Io = 50.1 b. 10*Log(I1/Io) = -32 db Log(I1/Io) = -3.2 I1/Io = 0.00063

physics
Vs = 332 m/s @ 0oC. = Velocity of sound. Vs = 332m/s + (22-0)oC*0.6m/s/oC Vs = 332 + 13,2 = 345.2 m/s. @ 22oC. a. d = Vs*t = 345 * 0.8 = 276 m b. d1 = d V*T = Vs*(T+0.8) 3*10^8T = 345(T+0.8) 3*10^8T = 345T+276 3*10^8T = 276 T = 92*10^10^-8 s. d = V*T = 3*10^8 * 92*10^-8 = 276 m.

math
2L + 2W = 42 2*11 + 2W = 42 2W = 20 W = 10 L = 11

Physics
K = k1 + k2 = 35 + 55 = 90N/cm.

Math (Triangles)
A = B = (180-40.33)/2 = 69.83o = Base angles. sinA/a = sinC/c sin69.83/320 = sin40.33/c c*sin69.83 = 320*sin40.33 c = 320*sin40.33/sin69.83 = 220.6 mm Or cosA = 0.5*AB/AC AC*cosA = 0.5*AB AB = 2AC*cosA = 2*320*cos669.83=220.7 mm

Discrete Mathematics
Year 1--2013--3^0*500 = 500 Rabbits Year 2--2014--3^1*500 = 1500 Year 3--2015--3^2*500 = 4500 Year n--20xx--3^(n-1)*500 = 100,000 3^(n-1)*500 = 100000 3^(n-1) = 200 (n-1)*Log 3 = Log 200 n-1 = Log 200/Log 3 = 4.82 n = 5.82 or 6 Yrs.

Discrete Mathematics
Fx) = 2x + 3*1/x F(x) = 2x + 3/x

hs math
P = 249.73/mo * 72mo = $17,980.56 P = (Po*r*t)/(1-(1+r)^-t) = 17,980.56 r = (3.599%/12)/100% = 0.0029992 = Monthly % rate expressed as a decimal. (Po*0.0029992*72)/(1-(1.0029992)^-72)= 17,980.56 Po*0.21594/(1-(1-(1.0029992)^-72)=17980.56. 0.21594Po/0.19396 = 17980.56 1.11332Po...

physics
Eq1: 4*t = d Eq2: 5*t = 6 + d In Eq2, replace d with 4t: 5t = 6 + 4t 5t-4t = 6 t = 6 s. In Eq1, replace t with 6: d = 4 * 6 = 24 m.

physics
L1 = 0.810 m. Temp. Change = +18o C. T.C. = 1.9*10^-5/C a. T^2 = 4pi^2(L/g) T^2 = 39.4(0.81/9.8) = 3.25653 T = 1.8046 s. b. L2 = L1 + L1*(T.C.)*18 L2=0.81 + 0.81(1.9*10^-5)*18=0.81027702 m. T^2 = 39.4(0.81027702/9.8)=3.25764 T = 1.8049 s. Change in period = 1.8049-1.8046 = 0.0...

physics
m1*g = 0.30kg * 9.8N/kg = 2.94 N. L1 = 0.26 m. m2*g = 1.90kg * 9.8N/kg = 18.62 N. L2 = 0.75 m. a. K = (N2-N1)/(L2-L1) K = (18.62-2.94)/(0.75-0.26) = 32 N/M b. (2.94N/32N) * 1M = 0.092 M. L + 0.092 = 0.26 L = 0.26 - 0.092 = 0.168 M.

General Physics
Wt. of block=m*g = 4kg * 9.8N/kg=39.2 N. Et = Ek + Ep = 0.5m*V^2 Ek + Ep = 0.5*4*(5.1)^2 = 52 J. 0 + Ep = 52 @ hmax. Ep = 52 @ hmax Ep = mg*h = 52 39.2h = 52 h = 1.33 m. Dist. up ramp = h/sinA = 1.33/sin13= 5.91 m.

General Physics
F1 = (0.2m/1m) * 28N = 5.6 N. To stretch spring 0.2 m. Work = F1 * d = 5.6 * 0.2 - 1.12 J. F2 = (0.2m+0.06m)/1m) * 28 N.=7.28 N. Work = F2 * d = 7.28 * 0.26 = 1.89 J. 1.89-1.12 = 0.77 J. to stretch it an additional 0.06 m.

General Physics
m*g = 7453 N. m*g = 7453 N. Fp = 7453*sin25.9 = 3256 N. = Force parallel to incline. Fap = Fp = 3256 N. = Force applied. Work = F * d = 3256 * 4.04 = 13,152 J. fp =

geometry
<1 = <2 = 4x-9 = 63o. 4x-9 = 63 4x = 63+9 = 72 X = 18o. The value of 9 is 9.

physics
Vo = 60km/hr = 60000m/3600s = 16.67 m/s. V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d a = (0-(16.67)^2)/60 = -4.63 m/s^2. Wt. of car = m*g = 15000 N. mass = 15000/9.8 = 1531 kg F = m*a = 1531 * -4.63 = -7.1 N.

physics
a=(V-Vo)/t = (-48.4--43.8)/1.08=-85.37 m/s^2. F = m*a = 0.148 * -85.37 = -12.6 N.

Math
3^2 + 3 = 12. Units digit = 2.

calculus
V^2 = Vo^2 + 2g*h h = (V^2-Vo^2)/2g h = ((190)^2-(30)^2)/64 = 550 Fi.

compound intrest
T = 365 + 57 = 422 Days. r = (3.5%/365)/100% = 9.58904*10^-5 = Daily % rate expressed as a decimal. I = Po*r*T I= 32000*0.00009589*422 = $1294.90

Physics
Vc = 81000m/3600s = 22.5 m/s. = Velocity of car. F = ((V+Vr)/(V+Vc)))*Fh = 958Hz. ((345+22.5)/(343-22.5))*Fh = 958 367.5Fh/322.5 = 958 1.140Fh = 958 Fh = 841 Hz. = Freq. of horn.

Physics
A. h = Vo*t + 0.5g*t^2 = 0.481 m. 0 + 4.9t^2 = 0.481 t^2 = 0.09816 t = 0.313 s. Each ball. B. V = Vo + g*t V = 0 + 9.8*0.313 = 3.07 m/s. Each ball.

algebra
2^3*sqrt(18)/6 = 8*sqrt(9*2)/6 = 8*3*sqrt(2)/6 = 24*sqrt(2)/6 = 4*sqrt(2). sqrt means square root.

science
See previous post.

science
A = 5m[240o] B = 2.5+6i C = -2.5i X = 5*cos240 + 2.5 = 0 Y = 5*sin240 + 6 - 2.5 = -0.83 D = 0-0.83i = 0.83m[-90o].

general physics
V^2 = Vo^2 + 2g.h Vo^2 = V^2-2g.h Vo^2 = 0-(-19.8)*190sin13 = 837.7 Vo = 28.9 m/s.

dynamics
See 10:35am post.

Dynamics
Ek = 0.5m*V^2 *h - = 750 * 6^2 = 27,000 J. Wt. = Fg = 1500kg * 9.8N/kg = 14,700 N. Ep = Fg * h = 27000-Fk*d 14700*5*sin20 = 27000-Fk*5 25138.5 = 27000-5Fk 5Fk = 27000-25138.5 = 1861.5 Fk = 372 N.

dynamics
V^2 = Vo^2 + 2g*h h = (V^2-Vo^2)/2g h = (0-625)/-19.6 = 31.89 m. NOTE: V = 0 @ max. Ht.

general physics
Di + Db = Dsw 917 + Db = 1025 kg/m^3 Db = 108 kg/m^3 = Density of the bear. Mass of bear = 6.76m^3*108kg/m^3=730 kg Wt. of bear = 730kg * 9.8N/kg = 7154 N.

science
CORRECTION: Ek = 84.672 J.

science
V^2 = Vo^2 + 2g*d Vo^2 = V^2-2g*d Vo^2 = 0-(-19.6*1.2 = 23.52 Vo = 4.85 m/s. Ek = 0.5m*Vo^2 = 3.6*(4.85)^2 = 11.76 J. vo^2

MATH
h = 125-5t^2 = 0 -5t^2 + 125 = 0 t^2 - 25 = 0 (t+5)(t-5) = 0 t = -5 t = 5 s. V = g*t = 9.8 * 5 = 49 m/s.

physics
Vs = 25 m/s = Velocity of the source. F = 260 Hz(NOT 26Hz). Fo = 240 Hz. Vr = Velocity of the receiver(person) F = (V+Vr)/(V-Vs)*Fo = 260 Hz. (V+0)/(V-25)*240 = 260 240V/(V-25) = 260 240V = 260V - 6500 -20V = -6500 V = 325 m/s.

Math
P = (Po*r*t)/(1-(1+r)^-t) Po = $81,000. r = (9%/12)/100% = 0.0075 = Monthly % rate expressed as a decimal. t = 25yrs. * 12mo/yr. = 300 Months. Plug the above values into the given Eq and get: P = $203,924.72 Monthly Payments = P/t Monthly Int. = (P-Po)/t. Monthly Prin. = (P/t)...

physics/science
See previous post.

physhcs
Xc = 1/W*C = 1/314.2*3*10^-6 = 1061 Ohms Z = R-jXc = 500 -j1061 = 1173[-64.8o]. 1. I = V/Z=12/1173[-64.8o]=0.01023[64.8] 2. Vc= I * Xc = 0.01023[64.8]*1061[-90o]= 10.85 Amps.[-25.2o] 3. A = -25.2o 4. P = I^2*R = (0.01023)^2 * 500= 0.0523 W. 5. Pf = cosA = cos(-64.8) = 0.426

phys ics
b. V = (0.243/0.335) * 28m/s = 20.3 m/s.

physics
Circumference=pi*2r=3.14*0.67=2.1=2.1 m. Va = 24.1m/s * 6.28rad/2.1m=72.1 rad/s.

physics
d = 0.5g*t^2 = 5.95 m. 4.9t^2 = 5.95 t^2 = 1.21 s. t = 1.10 s. 2.55rev/s * 1.1s = 2.8 revs.

physics
a. 28.9rad/s * 1rev/6.28rad = 4.60 rev/s. t = (13.6/4.60) * 1s = 3.0 s. b. V = Vo + at = 0 When @ rest. 28.9 + a*3 = 0 3a = -28.9 a = -9.63 rad/s^2.

physics
a. d = 2870rev * 6.28rad/rev = 18,024 rad. t = 18,024rad/131rad/s = 138 s. V = Vo + a*t = 131 rad/s Vo + 0.170*138 = 131 Vo = 131-23.4 = 108 rad/s. b. t = 138 s.

physics
V = Vo + at = 4.4 rad/s. 0 + 4.2t = 4.4 t = 4.4/4.2 = 1.05 s.

physics
d1 + d2 = 2pi rads = A complete circle. V1t + V2t = 2pi 2.46*10^-3 + 7.91*10^-3 = 6.28 10.37*10^-3t = 6.28 t = 606 s.

Math
See previous post.

Math
See previous post.

Math
Eq1: x^2 + y^2 = 34 Eq2: x + y = 2 x + y = 2 Y = 2 - x In Eq1, replace Y with 2 - x. x^2 + (2-x)^2 = 34 x^2 + 4 - 4x + x^2 = 34 2x^2 -4x + 4 = 34 2x^2 -4x - 30 = 0 Divide both sides by 2: x^2 - 2 - 15 = 0 (x+3)(x-5) = 0 x+3 = 0 X = -3. Y = 2- x = 2-(-3) = 5 x-5 = 0 X = 5. Y = ...

physics
Wt. = (6.0/1.0)^2 * 45.8 = 1649 N.

Elementary mechanics
My answer is the Rise Time or time to reach max. height. R = Vo*cosA * (Tr+Tf) Tr = Tf. Therefore, R = Vo*cosA * 2Tr. Tr = Rise time. Tf = Fall time. Vo*cosA = Hor. component of initial velocity.

Physics
Circumference=pi*D = 3.14 * 41=128.8 cm= 1.288 m. Vo = (86rev/min)*1min/60s*1.288m/rev = 1.85 m/s. V = (342/86) * 1.85 = 7.34 m/s a=(V-Vo)/t = (7.34-1.85)/3.4=1.61 m/s^2 d =Vo*t + 0.5*a*t^2 d=1.85*3.4 + 0.5*1.61*(3.4)^2= 15.6 m.

physics
Wt. = Fg = m*g = 60kg * 9.8N/kg=588 N.= Wt. of skier. Fp=588*sin35 = 337 N.=Force parallel to incline. Fv = 588*cos35 = 482 N. = Force perpendicular to incline. Fk = u*Fv = 0.08 * 482 = 38.5 N. = Force of kinetic friction. d =h/sinA = 2.5/sin35 = 4.36 m. Ek + Ep = Ekmax - Fk*d...

Physics
Wt. = m*g = 10kg * 9.8N/kg = 98 N. = Wt. of the luggage. F = 98N.[60o] = Force of luggage. Fp = 98*sin60 = 84.9 N. = Force parallel to incline. Fv=98*cos60 = 49 N.=Force perpendicular to incline = Normal. a. Work=mg * h = 98 * 6.5sin60= 552 J. b. Work = -98 * 6.5sin60 = -552 J...

physics
Density of water = 1000kg/m^3. V = 3m * 0.20m * 0.05m = 0.03 m^3=Vol. of board. 1 - (350/1000) = 0.65 = 13/20.

Physics
Impulse = m*V1-m*V2 Impulse = 2.4*2.5 - 2.4*1.5 = 2.4kgm/s

Elementary mechanics
F1 = 100[170o] F2 = 100[50o] X = 100*cos170+100*cos50o = -34.2 N. Y = 100*sin170+100*sin50 = 94 N. tan Ar = Y/X = 94/-34.2 = -2.74838 Ar = -70o = Reference angle. A = -70+180 = 110o Fr = X/cosA = -34.2/cos110 = 100N.[110o]

Trigonometry
Draw a picture of the situation: 1.Draw ver. line AC with A on the bottom. 2. Add point D on line AC. 3. Draw a hor. line from A to the left. Label it AB. Now we have a rt angle. 4. Draw hyp. BC. 5. Draw hyp. BD. <ABC = <ABD + <DBC = 61.5o 56.33 + <DBC = 61.5 <D...

Physics
T^2 = 4*pi^2(L/g) 1a. Longer. A smaller g increases the ratio of L/g which increases the period. 1b. Unchanged. The mass is not included in the Eq. 1c. Shorter. The ratio of L/g decreases which decreases the period. 1d. Unchanged. The ratio of L/g remains the same. Therefore, ...

science
The 100W bulb.

Physics
Wc = m*g = 1650kg * 9.8N/kg = 16,170 N.= Wt. of car. k = 16,170N./3.5m. = 4620 N/m.

Physics
Wc = m*g = 1840kg * 9.8N/kg = 18032 N. = Wt. of car. Fc = 18,032N[12.5o] = Force of the car. Fp = 18,032*sin12.5 = 3903 N. = Force parallel to incline. F-Fp = m*a = m*0 = 0 F-3903 = 0 F = 3903 N. Parallel to the incline Work = F*d = 3903 * 14 = 54,642 J.

physics
g = 9.8/6 = 1.633333 m/s^2 on moon. d = o.5g*t^2 = 50 m. 0.5*1.63333*t^2 = 50 0.81666t^2 = 50 t^2 = 61.22 t = 7.82 s.

physics
b. Fn = m*a a = Fn/m = (940-521)/95.9 = 4.37m/s^2. V = Vo + a*t = 0 Vo = -a*t = -(-4.37*1.63) = 7.1 m/s.

physics
Wp = m*g = 95.9kg * 9.8N/kg = 940 N. = Wt. of player. a. Fk = 0.554 * 940 = 520.7 N.

physics
CORRECTION: b. hmax = 3 + 0.141 = 3.141 m.

physics
a. V^2 = Vo^2 + 2g*h h(up) = (V^2-Vo^2)/2g. h(up) = (0-2.76)/-19.6 = 0.141 m. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6(0.141+3) = 61.6 V = 7.85 m/s. b. 0.141 m.

math
See previous post: 7:09pm.

Physics
d = 0.5g*t^2 = 122.5 m. 4.9t^2 = 122.5 t^2 = 25 t = 5 s. = Fall time. d = r*t = 122.5 m. 343t = 122.5 t = 0.357 s. T = 5 + 0.357 = 5.357 s.

physics
a. Y^2 = Yo^2 + 2g*h = 0 @ max. ht. Yo^2 = -2g*h = 19.6 * 21.8 = 427.28 Yo = 20.7 m/s. = Ver. component of initial velocity. Yo = 51.2*sin A = 20.7 m/s. sinA = 20.7/51.2 = 0.40373 A = 23.8o. Vo = 51.2[23.8o] Xo = 51.2*cos23.8 = 46.8 m/s. = Hor. component of initial velocity. V...

physics
F = m*g = 0.662 * 9.8 = 6.49 N. a. Work=F*d=6.49 * (6.32-1.82)=29.2 J. b. PE = mg*h = 6.49 * 6.32 = 41.0 J. c. PE = 6.49 * 1.82 = 11.81 J. d. 11.81 - 41 = -29.2 J.

physics
V^2 = Vo^2 + 2g.h Vo^2 = V^2-2g.h Vo^2 = 0-(-19.6)*190sin13 = 837.7 Vo = 28.9 m/s

physics
CORRECTION: Vo^2 = 9.8*190/sin26 = 4247.54 Vo = 65.2 m/s.

physics
D = Vo^2*sin(2A)/g = 190 m. Vo^2*sin(26)/9.8 = 190 Vo^2 = 190/sin26 = 433.4 Vo = 20.8 m/s.

MATH
P(t) = 20(4t+3)/(2t+5) a. Population in 1990: Let t =0. Solve for P and get 12,000. Population in 2000: Let t = 10. P = 34,400. Population in 2010: Let t = 20. P=36,889. Therefore the population is growing. b. Replace P with 50 and solve for t. You should get -9.5 years. The t...

physics
V^2 = Vo^2 + 2a*d a=(V^2-Vo^2)/2 a = ((2.1)^2-0)/19.2=0.230 m/s^2 Fn = m*a (Fap-Fk) = m*a (29-Fk) = 17*0.230 29-Fk = 3.91 Fk = 29-3.91 = 25.1 N. Ws = m*g = 17kg * 9.8N/kg = 167 N. = Wt. of sled. u = Fk/Ws = 25.1/167 = 0.150 = Coefficient of kinetic friction.

physics
Wc = m * g = 1310kg * 9.8N/kg = 12838 N. Fp = 12338*sin9.12o = 2035 N. = Force parallel to road. Fv = 12838*cos9.12 = 12676 N. = Force perpendicular to road. = The normal. Work = Fn * D = 155,00 J. Fn * 337 = 155000 Fn = 460 N. = Net force. Fn = F-Fp-Fk = 460 N. F-2035-541 = 4...

physics
a. F*cos23.2-48.5 = m*a = m*0 = 0 Fcos23.2 = 48.5 F = 48.5/cos23.2 = 52.8 N. b. Work = F*d = 52.8 * 34 = 1795 Joules. c. Work = Fk * d = 48.5 * 34 = 1649 J.

math
-16x^2 + 160t The max. point on the parabola is the vertex: t = Xv = -B/2A = -160/-32 5 s hmax. = Yv = -16*5^2 + 160*5 = 400 Ft. V(5,400).

Geometry
1. A = 400cm * 2cm = 800 cm^2. 2. A = (3.5^2) = 3. A = pi*r^2 = 3.14 * (9/2)^2 =

algebra1 HELP PLEASE
Let y = 0. x^2-7 = 0 x^2 = 7 X = =+-sqrt 7

algebra1 HELP PLEASE
h1(t) = 100 - 0.5*32*t^2. h1 = 100 - 16t^2 = 0 @ gnd. level. 16t^2 = 100 t^2 = 6.25 t = 2.50 s. h2(t) = 210 - 0.5*32*t^2 h2 = 210 - 16t^2 = 0 @ gnd. level. 16t^2 = 210 t^2 = 13.125 t = 3.62 s.

Pages: <<Prev | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | Next>>

Search
Members