Saturday

August 30, 2014

August 30, 2014

Total # Posts: 8,960

**physical science**

d = 80m/s * 30min * 60s/min = 1440 m. W = F*d = 40 * 1440 = 57,600 Joules.
*October 27, 2013*

**physics**

d = Vo*t + 0.5g*t^2 d = 0 + 4.9*58^2 = 16,484 m.
*October 27, 2013*

**physics mechanics**

Wm = m*g = 2kg * 9.8N/kg = 19.6 N. = Wt. of the mass. Fap-Fs = m*a Fap-u*mg = m*0 Fap-0.7*19.6 = 0 Fap=13.72 N. = Force applied by spring. d = (13.72N/200N) * 1m = 0.0686 m. = distance the spring is stretched. Fn = Fap - Fk = 13.72-0.5*19.6 = 3.92 N. = Net Force. a = Fn/m = 3....
*October 26, 2013*

**science**

50 + 48 = 98 km/h.
*October 26, 2013*

**physics**

YES!
*October 26, 2013*

**physics**

Work = F * d So when an object is moved a certain distance by a force acting in the direction of the motion, work is done on the object.
*October 26, 2013*

**physics (science)**

D = 1km[90o] + 1.2km[50o] + 0.8km[25o] X=1*cos90 + 1.2cos50 + 0.8*cos25=1.50 km Y=1*sin90+1.2*sin50+0.8*sin25=2.257 km tanA = Y/X = 2.257/1.50 = 1.50892 A = 56.5o = Direction. D = Y/sinA = 2.257/sin56.5=2.71m[56.5o].
*October 25, 2013*

**business math**

P = Po(1+r)^n = $225,000 r = (8%/2)/100% = 0.04 = Semi-annual % rate expressed as a decimal. n = 2Comp./yr * 15yrs = 30 Compounding periods. Po*(1.04)^30 = 225,000 Po = 225,000/1.04^30 = $69,371.70
*October 25, 2013*

**Physics**

Vb = 0.54m/s[-45o] Vr = 0.60m/s[0o] X = 0.54*cos(-45) + 0.60 = 0.982 m/s. Y = 0.54*sin(-45) + 0 = -0.382. tan A = Y/X = -0.382/0.982 = -0.38884 A = -21.2o = Direction. Vb'=X/cosA = 0.982/cos(-21.2)= 1.053m/s[-21.2o] or 21.2o S. of E.
*October 25, 2013*

**math**

See previous post:Tue,10-22-13,1:59 PM.
*October 24, 2013*

**math**

See previous post: Tue,10-22-13,1:59 PM.
*October 24, 2013*

**Physics**

Wb = 2.6kg * 9.8N/kg = 25.48 N. 203N/1m = F/-0.115 F=-0.115*203=-23.35 N. a = F/m = -23.35/2.60 = -8.98 m/s^2.
*October 24, 2013*

**physics**

See previous post: Thu,10-24-13,3:05 PM.
*October 24, 2013*

**Physics**

1. X = 36 * 0.7 = 25.2 Volts 2. Y = 4A 3. Voc = 34 * 0.7 = 23.8 Volts.
*October 24, 2013*

**physics**

Correction: Pe=102.9 * 15/20 = 77.18 J/s=77.18 Watts = Power exerted.
*October 24, 2013*

**physics**

F = m*g = 21kg * 9.8N/kg = 205.8 N. Fk = u*mg = 0.5 * 205.8 = 102.9 N.=Force of kinetic friction. Fe-Fk = m*a Fe-102.9 = m*0 = 0 Fe = 102.9 N. = Force exerted. Pe = Fe * d/t = 102.9 * 15/20 = 77.18 N. = Power exerted.
*October 24, 2013*

**physics**

F = m*g = 200kg * 9.8N/kg = 19,600 N. P = F * h/t = 19600 * 6/3600s.=32.67 J/s = 32.67 Watts. (32.67/746) * 1hp = 0.0438 hp.
*October 24, 2013*

**physics**

A = Theta. W = (F*cosA) * V*t. P = (F*cosA) * V
*October 24, 2013*

**math**

25-(6+7+4) = 25 - (6+7+4) = 9
*October 24, 2013*

**physics**

L = h/sinA = 2.90/sin30 = 5.80 m. = Length of incline. Wb = = m*g = 3kg * 9.8N/kg = 29.4 N. = Weight of box. Fp = 29.4*sin30 = 14.7 N. = Force parallel to incline. Fv = 29.4*cos30 = 25.46 N. = Force perpendicular to incline. Fk = u*Fv = 0.06*25.46 = 1.53 N. = Force of kinetic ...
*October 24, 2013*

**Physics**

V^2 = Vo^2 + 2a*d V^2 = 0 + 8.6*43 = 369.8 V = 19.23 m/s At the edge of ihe cliff. Vo = 19.23m/s[-22o] At the edge of the cliff. Xo = 19.23*cos(-22) = 17.83 m/s. Yo = 19.23*sin(-22)=-7.20 m/s.=7.20 m/s, downward. a. h = Yo*t + 0.5g*t^2 = 33 m. 4.9t^2 + 7.2t - 33 = 0 Use ...
*October 23, 2013*

**physics**

Incomplete.
*October 23, 2013*

**Math**

X = Student tickets sold. Y = Adult tickets sold. Eq1: x + y = 50 Tickets. Eq2: 2x + 3y = $135. Multiply Eq1 by -2 and add the Eqs: -2x - 2y = -100 2x + 3y = 135 Sum: Y = 35 In Eq1, replace Y with 35: x + 35 = 50 X = 15
*October 23, 2013*

**Math- URGENT**

m = (-8-y)/(15-12) = 2/3 -24-3y = 30-24 -3y = 30 Y = -10
*October 23, 2013*

**Algebra**

Beth: t hours. Clara:(t+2) Hours. Eq1: r*t = 100 mi Eq2: r*(t+2) = 220 mi. r*t + 2r = 220 Replace r*t with 100: 100 + 2r = 220 2r = 120 r = 60 mi./h. In Eq1, replace r with 60: 60t = 100 t = 1.66 Hours. = Beth's driving time.
*October 23, 2013*

**TO ALL TEACHERS**

I'm delighted to know that we were able to help you and others, I wish you continued success.
*October 23, 2013*

**Physical science**

Correction: P = F * d/t=96 * 2.8/4.6=58.43 J/s = 58.43 Watts.
*October 23, 2013*

**Physical science**

P = F * d/t = 96 * 1.2/4.6 = 25.04 J/s.= 25.04 Watts.
*October 23, 2013*

**physics**

a = (V-Vo)/t = (18-0)/12 = 1.5 m/s^2. Wt = m*g = 1500kg * 9.8N/kg = 14,700 N. d = 0.5a*t^2 = 0.75*12^2 = 108 m. Fe-400 = m*a Fe-400 = 1500*1.5 = 2250 Fe = 2250 + 400 = 2650 N. = Force of engine. Power=Fe * d/t=2650 * 108/12=23,850 J/s = 23.850 Watts.
*October 23, 2013*

**Physics**

Incomplete.
*October 23, 2013*

**Physics**

Wb = m*g = 90kg * 9.8N/kg = 882 N. = Wt of block. a. Deflection=882/5000 * 1m = 0.1764 m. b. Same as a.
*October 23, 2013*

**Physics**

a. V = d/t = 2.0m/1.75s. = 1.143 m/s. V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d a = (1.143^2-o)/4 = 0.327 m/s^2 b. Wb = m*g = 3kg * 9.8N/kg = 29.4 N. = Weight of block. Fp = 29.4*sin25.5 = 12.66 N. = Force parallel to incline. Fv = 29.4*cos25.5 = 26.54 N. = Force perpendicular to ...
*October 23, 2013*

**physics**

Wc = m*g = 19kg * 9.8N/kg = 186.2 N. = Weight of crate. Fap-Fs = m*a 83-u*mg = m*0 83-u*186.2 = 0 186.2u = 83 us = 0.446 uk*186.2 = 53 uk = 0.285
*October 23, 2013*

**physic**

g = 9.8 m/s^2
*October 22, 2013*

**Finance**

a. 1/A = 0.08 0.08A = 1 A = $12.5 Million. b.
*October 22, 2013*

**science**

1. mass/cm^3 = Density = 20g/10cm^3 = 2g/cm^3 = 0.002kg/cm^3. 2. Density = 125g/25cm^3 = 5 g/cm^3 = 0.005kg/cm^3.
*October 22, 2013*

**math**

r1 = 40km/0.5h = 80 km/h = Stephen's speed. r2=Cole's speed = 80 + 30 = 110 km/h. r2 * t = (r1 * t) + 40km 110t = 80t + 40 30t = 40 t = 1.33 h. D = r*t = 110 * 1.333 = 146.7 km. = Distance between the 2 towns.
*October 22, 2013*

**physics**

d = 100 - 50 = 50 Meters.
*October 22, 2013*

**MATH**

Marit ate 12 crackers/day. Jennifer ate 12+6 = 18 crackers/day. Difference = 96-24 = 72 crackers 72Crackers/6Crackers/day = 12 Days Marit=12crackers/day * 12Days=144 Crackers. Jennifer=18crackers/day*12days=216 crackers.
*October 22, 2013*

**Math**

X = # of oranges. X = # of pears. ($2/7) * X = $Y Multiply both sides by 7: 2x = 7y Eq1: 2x - 7y = 0 ($3/5) * X = y + 33 Multiply both sides by 5: 3x = 5y + 165 Eq2: 3x - 5y = 165 Multiply Eq1 by 3 and Eq2 by -2 and add: +6x - 21y = 0 -6x + 10y = -330 Sum: -11y = -330 Y = $30...
*October 22, 2013*

**GEOMETRY**

5*Sqrt(3/3)=5*Sqrt(1)=5*1 = 5.
*October 21, 2013*

**Physics**

Tf = Tr = 2.80 s. = Fall time.
*October 21, 2013*

**Physics**

Vp + Vw = 410mi/h[310o]+50mi/h[295o]. X = 410*cos310 + 50*cos295 = 284.7 mi/h Y = 410*sin310 + 50*sin295 = -359.4 mi/h tanA = Y/X = -359.4/284.7 = -1.26236 A = -51.6 = 51.6o S. of E. Vr = Y/sin(-51.6) = 459 mi/h
*October 21, 2013*

**physics**

Incomplete.
*October 21, 2013*

**physics**

1. V = a * t = 20 m/s. a * 10 = 20 a = 2 m/s^2. 2. V = Vo + a*t = 0 20 + a*20 = 0 20a = -20 a = -1.0 m/s^2.
*October 21, 2013*

**Physics**

Fg = m*g = 10kg * 9.8N/kg = 98 N. d = (98/400) * 1m = 0.245 m.
*October 21, 2013*

**physics**

1. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*3 = 58.8 V = 7.67 m/s. 2.
*October 21, 2013*

**Physics**

(1/12) * 60s = 5 s. per brick. P = F * d/t = mg * d/t P = 3.75*9.8 * 3.3/5=24.26 J/s=24.26 W. (24.26/746) * 1hp = 0.0325 hp.
*October 21, 2013*

**phyics**

V^2 = Vo^2 + 2g*h (Vo/2)^2 = Vo^2 + 2g*h Vo^2/4 = Vo^2 - 19.6*5 Vo^2/4 = Vo^2 - 98 Multiply both sides by 4: Vo^2 = 4Vo^2 - 392 4Vo^2 - Vo^2 = 392 3Vo^2 = 392 Vo^2 = 130.7 Vo = 11.43 m/s. hmax = (V^2-Vo^2)/2g h max = (0-11.43^2)/-19.6 = 6.67 m.
*October 20, 2013*

**Physics**

Incomplete.
*October 20, 2013*

**physics**

CORRECTION: Y^2 = 0 + 19.6*(4.82-3) = 35.67 Y = 5.97 m/s.
*October 20, 2013*

**physics**

Vo = 14.2m/s[43.2o] Yo = 14.2*sin43.2 = 9.72 m/s. hmax = (Y^2-Yo^2)/2g hmax = (0-9.72^2)/19.6 = 4.82 m. Y^2 = Yo^2 + 19.6*h Y^2 = 9.72^2 + 19.6*(4.82-3) = 130.15 Y = 11.41 m/s
*October 20, 2013*

**Physics**

Incomplete.
*October 20, 2013*

**physics**

Fn = mg*cos16 = 5.7*9.8*cos16 = 53.7 N.
*October 20, 2013*

**physics**

Dx = Vx * Tf = 20 m. 27.1 * Tf = 20 Tf = 0.738 s. = Fall time. h = Yo*Tf + 0.5g*Tf^2 h = 0 + 4.9*0.738^2 = 2.67 m.
*October 20, 2013*

**physics**

Va = 72rev/2s * 1cy/rev = 36/cycles/s.
*October 20, 2013*

**Physics**

Fg = m*g = 0.245kg * 9.8N/kg = 2.401 N.= Force of gravity. D = d1 + d2 d1=(V^2-Vo^2)/2g=(0-8.8^2)/-19.6=3.951 m Up. d2 = d1 + 2.20 = 3.951 + 2.20 = 6.15 m, Down. Wg = Fg*(d1+d2)=2.401*(3.951+6.15)=24.3 Joules.
*October 20, 2013*

**Physics**

See previous post: Sun,10-20-13,2:57 PM.
*October 20, 2013*

**Physics**

Fx = 35.9*cos28.7 = 31.49 N. = Hor. component. Work=Fx*d = 31.49 * 3.41 = 107.4 Joules
*October 20, 2013*

**Physics**

X = 3 m/s. Y = -2 m/s. a. (Vr)^2 = X^2 + Y^2 = 3^2 + (-2)^2=13 Vr = 3.61 m/s. = Resultant velocity. b. tan A = Y/X = -2/3 = -0.66666 A = -33.7o = 33.7o S. of E. Therefore, she must swim 33.7o N. of E.
*October 20, 2013*

**Projectile motion**

h = (Vo*sin(-30))*(t) + 0.5g*t^2=15 m. (Vo*sin(-30))*(3) + 4.9*3^2 = 15 -1.5Vo + 44.1 = 15 -1.5Vo = 15-44.1 = -29.1 Vo = 19.4 m/s.
*October 20, 2013*

**math**

Incomplete.
*October 20, 2013*

**Science/Physics**

Very fast!
*October 20, 2013*

**PHYSICS**

V^2 = Vo^2 + 2g*h h = (V^2-Vo^2)/2g h = (0-5^2)/-20 = 1.25 m. V = Vo + g*t t = (V-Vo)/g = (0-5)/-10 = 0.5 s.
*October 19, 2013*

**physics**

See previous post.
*October 19, 2013*

**physics**

Correction: Fv = 49,000*cos15 = 47,330 N,
*October 19, 2013*

**physics**

W = m*g = 5000kg * 9.8N/kg = 49,000 N.= Weight of truck. Fp = 49000*sin15 = 12,682 N. = Force parallel to ramp. Fv = 4900*cos15 = 47,330 N. = Force perpendicular to the ramp. Fk = u*Fv = 0.10 * 47,330 = 4733 N. = Force of kinetic friction. T-Fp-Fk = m*a T-12682-4733 = m*0 = 0 ...
*October 19, 2013*

**Finance**

P = n*Po*(1+r)^t P = 4*6400(1.057)^4 = $31,955.08
*October 19, 2013*

**Physics**

1. d = 0.5g*t^2 = 3 m. 4.9t^2 = 3 t^2 = 0.6122 T = 0.782 s. To cross canyon. 2. 3 m.
*October 17, 2013*

**Physics**

C = (14/500) * 1m = 0.028 m.
*October 17, 2013*

**Math**

1.23*10^-10/1.4*10^-8 = 0.879*10^-2 = 8.79*10^-3. When dividing, subtract the exponents: -10 - (-8) = -10 + 8 = -2.
*October 17, 2013*

**Physics**

See previous post: 10-17-13,5:26 PM.
*October 17, 2013*

**physics**

Wc = m*g = 3100kg * 9.8N/kg = 30,380 N.= Wt. of car. Fp = 30,380*sin19.5 = 10,141 N. = Force parallel to incline. Fv = 30,380*cos19.5 = 28,637 N. = Force perpendicular to incline. Fk=4400 N. = Force of kinetic friction. Fp-Fk = m*a a=(Fp-Fk)/m a = (10,141-4400)/3100=1.852 m/s^...
*October 17, 2013*

**physics**

1. V = 90km/h = 90000m/3600s. = 25 m/s. a = (V-Vo)/t = (25-0)/8 = 3.125 m/s^2. t = 42-18 = 24 s. To catch up. d = Vo*t + 0.5a*t^2 d = 0 + 0.5*3.125*24^2 = 900 m. 2. d = V*t = 900 m. V * 42 = 900 V = 21.43 m/s.
*October 17, 2013*

**physics**

Vo = a * t = 29.4 * 5.65 = 166.1 m/s. V^2 = Vo^2 + 2g*h h=(V^2-Vo^2)/2g=(0-166.1^2)/-19.6=1408 m
*October 17, 2013*

**maths**

See previous post.
*October 17, 2013*

**maths**

The 1st(closest) car: X1 = Distance from tower. A1 = 60o = Angle between X1 and hyp. The 2nd car: X2 = Dist. bet. the 2 cars. X1+X2 = Dist. from 2nd car to tower. A2 = 30o = Angle bet. (X1+X2) and hyp. tan 60 = 50/X1 X1 = 50/tan 60 = 28.87 m. tan 30 = 50/(X1+X2) X1+X2 = 50/tan...
*October 17, 2013*

**Physics**

If there is no angle between the vectors, the sum = 200 + 40 = 240.
*October 17, 2013*

**physics**

Xo = 2 m/s. h = 0.5g*t^2 = 1 m. 4.9t^2 = 1 t^2 = 0.204 Tf = 0.452 s. = Fall time. Dh = Xo * Tf = 2m/s * 0.452 = 0.904 m = Hor. distance from table. d = Dh - r = 0.904 - 0.05 = 0.854 m = Hor. distance from table.
*October 17, 2013*

**Physics**

See previous post: Wed,10-16-13,2:01 PM>
*October 16, 2013*

**Physics**

Dc = Vo*t + 0.5a*t^2 = 27t+60 41t + 0.5*5*t^2 = 27t + 60 41t -27t + 2.5t^2 = 60 14t + 2.5t^2 = 60 2.5t^2 + 14t - 60 = 0 Use Quadratic formula. t = 2.84 s. To catch up. Vc = Vo + a*t = 41 + 5*2.84 = 55.2 m/s.
*October 16, 2013*

**physics**

Incomplete.
*October 16, 2013*

**Physics**

Incomplete.
*October 16, 2013*

**Physics**

1. d = 1.7 + 7.1 + 3.5 = 12.3 km. 2. D = 1.7 -7.1 + 3.5 = -1.9 km = 1.9 km , West.
*October 16, 2013*

**Physics**

Ct = C1*C2/(C1+C2) = 8.3*2.9/(8.3+2.9) = 2.15 uF Qt = Ct*E = 2.15 * 24 = 51.6 uC.=Q1=Q2. Energy=0.5C*E^2 = 0.5*2.15*24^2 =619.2 Joules Parallel Combination: Ct = C1 + C2 = 8.3 + 2.9 = 11.2 uF. Energy = 0.5*Ct*E^2 = 619.2 Joules 0.5*11.2*E^2 = 619.2 5.6E^2 = 619.2 E^2 = 110.6 E...
*October 16, 2013*

**physics**

Please post your problem.
*October 16, 2013*

**Physics**

X = 75 m/s. Y = 100 m/s. Q1. tan A = Y/X = 100/75 = 1.33333 A = 53.1o V=Y/sin A = 100/sin53.1 = 125.0N.[53.1o] Q2. Direction = 90o-53.1o=36.9o W of N.
*October 16, 2013*

**Physics**

Same procedure as previous post
*October 16, 2013*

**Physics**

F = 152N[35o] Fx = 152*cos35 = Fy = 152*sin35 =
*October 16, 2013*

**Physics**

X = 13.5 N. Y = 32 N. tan A = Y/X = 32/13.5 = 2.37037 A = 67.1o Fr = 32/sin 67.1 = 34.7 N[67.1o] = Resultant force. Equilibrant=34.7N[67.1+180]=34.7N[247.1]
*October 16, 2013*

**Math- Urgent**

W/4 = -13 Multiply both sides by 4: W = 4*-13 = -52.
*October 16, 2013*

**Physics**

a. C = C1*C2/(C1+C2) = 30 uF 33.6*C2/(33.6+C2) = 30 33.6C2 = 1008+30C2 33.6C2-30C2 = 1008 3.6C2 = 1008 C2 = 280 uF In series. b. C1 + C2 = 30 uF 29.3 + C2 = 30 C2 = 30 - 29.3 = 0.7 uF in parallel.
*October 15, 2013*

**science**

Incomplete.
*October 15, 2013*

**physics**

Fap-Fk = m*a Eq1: 77 - Fk = m*0.45 Eq2: 82 - Fk = m*0.74 Subtract Eq2 from Eq1: Diff. = -5 = -29m m = 0.172 kg.
*October 15, 2013*

**Physical Science**

W = (1/6)(100kg*9.8N/kg) = 163.3 N.
*October 15, 2013*

**Physical Science**

d.
*October 15, 2013*

**math**

Scale = 1cm:0.6m = 1cm:60cm V = (60/1)*(34 x 20 * 6) V = 2040 x 1200 x 360 cm.
*October 15, 2013*

**Algebra 2**

24. Eq1: 4x + 5y = 3 Eq2: 6x + 9y = 9 Multiply Eq1 by 6 and Eq2 by -4 and add: 24x + 30y = 18 -24x - 36y = -36 Sum: -6y = --18 Y = 3 In Eq1, replace y with 3 and solve for x: 4x + 5*3 = 3 4x = 3-15 = -12 X = -3 26. Use same procedure as #24. Multiply Eq1 by 2 and Eq2 by -4 and...
*October 15, 2013*

**physics**

d = 2.12m/s * 0.21s = 0.4452 m. C=(6.28rad/2.10rad) * 0.4452 m=1.33 m. = Circumference. C =3.14 * 2r = 1.33 m. 6.28r = 1.33 r = 0.212 m. = Radius of the wheel.
*October 15, 2013*

**Physics**

V^2 = Vo^2 + 2a*d a = (V^2-Vo^2)/2d a = (372.4^2-0)/1 = 138,682 m/s^2 F = m * a = 0.0042 * 138,682 = 582.5 N.
*October 15, 2013*

Pages: <<Prev | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | **15** | 16 | 17 | 18 | 19 | 20 | 21 | Next>>