Monday

August 31, 2015
Total # Posts: 10,932

**College Physics**

d = V*t = 0.12 m t = 0.12/V = 0.12/7*10^7=1.71*10^-5 s.
*January 24, 2015*

**Physics**

Dc = 19t = Distance of the car after t1. Dm = Vo*t + 0.5a*t^2 = Distance of motorcycle after t1. Dm = Dc + 52 Vo*t + 0.5a*t^2 = 19t + 52 19*t + 2.5*t^2 = 19t + 52 19t - 19t + 2.5*t^2 = 52 t^2 = 20.8 t = 4.56 s. So the motorcycle caught-up 4.56 s after it started to accelerate.
*January 24, 2015*

**Physics**

V1/V2 = M2/M1 = 56kg/96kg = 0.583
*January 24, 2015*

**science**

a. Fx = 3000*Cos30 = 2598 N. b. Fy = 3000*sin30 = 1500 N. = Lifting force.
*January 24, 2015*

**Physics**

See previous post: Fri, 1-23-15, 5:42 PM.
*January 24, 2015*

**Physics**

V^2 = Vo^2 + 2a*d = 0 Vo^2 = -2a*d = -2*(-7.2)*72 = 1036.8 Vo = 32.2 m/s. = Speed before braking.
*January 23, 2015*

**math**

Let g = 10 m/s^2. d = 0.5g*t^2 = 5*9^2 = 405 m.
*January 23, 2015*

**physics**

Vo = 50m/s @ A Degrees Xo = 50*Cos A Yo = 50*sin A Y^2 = Yo^2 + 2g*h = 0 @ max ht. Yo^2 = -2g*h = -2*(-9.8)*100 = 1960 Yo = 44.27 m/s = Ver. component of initial velocity. Yo = 50*sin A = 44.27 sin A = 44.27/50 = 0.88544 A = 62.3o. = Angle of projection. Y = Yo + g*Tr = 0 Tr...
*January 23, 2015*

**science**

d1 + d2 = 12 m. d1 = Vo*t + 0.5g*t^2 d2 = 0.5g*t^2 16*t - 4.9*t^2 + 4.9*t^2 = 12 16*t = 12 t = 0.75 s.
*January 22, 2015*

**science**

a = (V-Vo)/t = 30-0)/10 = 3 m/s^2
*January 22, 2015*

**Physics**

P = F * d/t = M*g * d/t = 5*9.8 * 12/15 = 39.2 J/s = 39.2 Watts.
*January 22, 2015*

**physics**

Vo[51o] Xo = 7 m/s Vo = ? Xo = Vo*Cos51 = 7 m/s Vo = 7/Cos51 = 11.12 m/s = Initial velocity. Yo = Vo*sin51 = 11.12*sin51 = 8.64 m/s.
*January 22, 2015*

**physics**

Increase = (26-(-16))C*1.7*10^-5/C*30cm = 42*1.7*10^-5 * 30cm =0.02142 cm.
*January 22, 2015*

**math**

1. (7a^5-a^3) - (a^5-5a^3-1) Remove the parenthesis: 7a^5-a^3 - a^5+5a^3+1 Combine like-terms: 6a^5 + 4a^3 + 1
*January 22, 2015*

**Math**

(3x+4)*Log2 4 = (3x+4)*2 = 6x + 8.
*January 22, 2015*

**math**

h(t) = -4t^2 + 30t + 1.4 Tr = -B/2A = -30/-8 = 3.75 s. = Rise time. Tf = Tr = 3.75 s. = Fall time. Tr+Tf = 3.75 + 3.75 = 7.5 s. To get under the ball.
*January 22, 2015*

**Math**

X Girls. (x+45) Boys. 2x/3 girls passed the test. (4/5)(x+5) = (4x/5 + 4) boys passed test 49 Children failed the test. (x - 2x/3) = x/3 = Girls that failed the test. (X+45) - (4x/5+4) = x/5+41 Boys that failed the test. X/3 + (x/5+41) = 49 x/3 + x/5 = 49-41 = 8 Multiply both ...
*January 22, 2015*

**physics**

Incomplete.
*January 22, 2015*

**phyisics**

h = 1*sin30 = = 0.5 m. V1^2 = Vo^2 + 2g*h = 0 + 19.6*0.5 = 9.8 V1 = 3.13 m/s. M1*g = 25N. M1*9.8 = 25 M1 = 2.55 kg M2*9.8 = 40N. M2 = 4.08 kg M1*V1 + M2*V2 = M1*V + M2*V 2.55*3.13 + 4.08*0 = 2.55*V + 4.08*V 7.982 = 6.63V V = 1.20 m/s.
*January 22, 2015*

**Math**

1b.
*January 21, 2015*

**Physics**

X = 64.9 Y = ? Z = 87.6 = magnitude or hypotenuse. X^2 + Y^2 = Z^2 Solve for Y.
*January 21, 2015*

**Physics**

2.75*10^19electrons/30s = 9.167*10^17 electrons/s I = (9.167*10^17/62.42*10^17) * 1Amp = 0.147 Amps.
*January 21, 2015*

**physics**

Vo = 15.4m/s[34.7o] Xo = 15.4*Cos34.7 = 12.7 m/s. Yo = 15.4*sin34.7 = 8.77 m/s. Y = Yo + g*Tr = 0 @ max.ht. 8.77 - 9.8*Tr = 0 -9.8Tr = -8.77 Tr = 0.895 s. = Rise time. Tf = Tr = 0.895 s. = Fall time. Tr+Tf = 0.895 + 0.895 = 1.79 s. to hit gnd.
*January 21, 2015*

**physics**

h = Vo*t + 0.5g*t^2 Vo = 0 t = 2.88 s. g = 9.8 m/s^2 Solve for h.
*January 21, 2015*

**physics**

M2V2 = M1V1 0.00255*V2 = 10.7*4.26 Solve for V2.
*January 21, 2015*

**Math proportions**

(20min/150people) * 240people = 32 Min.
*January 21, 2015*

**Algebra 2**

g(x) = x^2 - 7x - 9 g(-1) = (-1)^2 - 7*(-1) - 9 = -1 F(g(-1)) = F(-1) F(x) = x - 2 F(-1) = -1 - 2 = -3.
*January 21, 2015*

**algebra**

m2 = m1 = -A/B = -1/1 = -1 P(0,0), m2 = -1 Y = mx + b = 0 -1*0 + b = 0 b = 0 Y = -1x + 0 Eq2: Y = -x
*January 21, 2015*

**7th grade math**

Both answers are correct!
*January 21, 2015*

**Algebra**

2(x+3) = 2x+3 2x+6 = 2x+3 2x-2x = 3-6 0 = -3? No
*January 21, 2015*

**algebra**

10in./30in. =
*January 21, 2015*

**Math (Greatest common factor)**

12 = (1*12), (2*6), (3*4). 18 = (1*18), (2*9), (3*6). 24 = (1*24), (2*12), (3*8), (4*6). CF = 1,2,3,6. GCF = 6. So we factor out 6 and the variables with the lowest exponents: 6m^2n^3(2m^3 + 3m - 4) I, normally, find the GCF by knowing that the GCF =< 12 (the smallest ...
*January 21, 2015*

**Math**

1. 6.4in * 2.54cm/in = 2. 4qts * 32oz./qt * 0.03L/oz. = 3. 10kg * 1Lb/0.454kg =
*January 21, 2015*

**physics**

A train whistle is heard at 280Hz as the train approaches town. The train cuts its speed in half as it nears the station, and the sound of the whistle is then 270 Hz. What is the speed of the train before slowing down? What is the speed of the train after slowing down?
*January 21, 2015*

**physics**

M1*V1 + M2*V2 = M1*V3 + M2*V3 V3 = V4. 60*0 + 15*12 = 60*V3 + 15*V3 180 = 75V3 V3 = 2.4 m/s = Velocity after impact.
*January 21, 2015*

**physics**

a. Y = Yo + g*t = 0 + 9.8*1 = 9.8 m/s = Ver Component. X-component = 0 b. D = 0.5*g*t^2. Solve for D. Y = D, X = 0.
*January 21, 2015*

**physic**

a. V = a*t = 0.5m/s^2 * 4s. = 2 m/s. b. d = 0.5a*t^2 = 0.5*0.5*4^2 = 4 m.
*January 21, 2015*

**Physics**

T = 12s./10rev = 1.2 s/rev.=1.2 s/cycle
*January 20, 2015*

**Math**

sqrt(450) = sqrt(2*225) = 15*sqrt(2).
*January 20, 2015*

**ascience**

X = 20 mi/h Y = 10 mi/h Tan A = Y/X = 10/20 = 0.50 A = 26.56o V = X/Cos A = 20/Cos26.56 = 22.4mi/h[26.56o]
*January 20, 2015*

**Physics**

Do you mean (5,7)? If so, (x,y) = 5,7).
*January 20, 2015*

**physics**

V = Vo + g*t V = 0 Vo = Initial velocity. g = -9.8 m/s^2 t = 2.2 s. Solve for Vo.
*January 20, 2015*

**Math**

Yes.
*January 20, 2015*

**math**

Bearing of Q = 90-50 = 40o East of North
*January 20, 2015*

**Math**

8/25 + 1/5 + x = 4/5 X = 4/5 - 8/25 - 1/5=20/25 - 8/25 - 5/25 = 20/25 - 13/25 = 7/25 of the grid for Nate.
*January 19, 2015*

**physics**

Dx = 1710*Cos5.08 =
*January 19, 2015*

**physics**

196m[-18o] X = 196*Cos(-18) = Y = 196*sin(-18) =
*January 19, 2015*

**grade 7 math**

1. -450 km/h(South). 2. 675 km/h(North). 675T - (-450T) = 3600 km. Solve for T.
*January 19, 2015*

**grade 7 math**

A = -80 km/h(West). B = 110 km/h(East). 110T - (-80T) = 760 km 110T + 80T = 760 190T = 760 T = 4 h.
*January 19, 2015*

**grade 7 math**

d1 + d2 = 210 km 60*2 + r2*2 = 210 Solve for r2.
*January 19, 2015*

**grade 7 math**

9:15 - 8:00 = 1h and 15 min. = 1.25h head-start. d = r1*t = 45km/h * 1.25h = 56.25 km Head-start. r2*t = r1*t + 56.25 t = 9:15AM to 1PM = 3h and 45min = 3.75h r2 * 3.75 = 45*3.75 + 56.25 r2*3.75 = 225 r2 = 60km/h = Michael's speed. r1*t + 56.25 = 45*3.75 + 56.25 = 225 km...
*January 19, 2015*

**grade 7 math**

d1 = r1*t1 = 60km/h * 0.5h = 30 km after 0.5 h. r2*t = r1*t + 30 65 * t = 60*t + 30 65t - 60t = 30 5t = 30 t = 6 hours.
*January 19, 2015*

**Physics/Math**

a. Eo/Ei = 1.0 100/Ei = 1 Solve for Ei. b. Eo/Ei = 0.30 Eo/100 = 0.30 Solve for Eo. c. Same procedure as a and b.
*January 19, 2015*

**physics**

A = 13.2[0o] B = 6.1[110o] R = 13.2+6.1*Cos110 + i6.1*sin110 = 11.11 + 5.73i R^2 = 11.11^2 + 5.73^2 = 156.3 R = 12.50
*January 19, 2015*

**physics**

1. D = Vo*t + 0.5a*t^2 = 6.1*6.8 * 0.5*0.49[35o]*6.8^2 = 41.48 + 11.33[35o] = 41.48 + 9.28+6.5.0i = 50.76 + 6.5i D^2 = 50.76^2 + 6.5^2 = 2618.3 D = 51 m. 2. Tan A = Y/X = 6.5/50.76 = 0.12805 A = 7.3o = Direction.
*January 18, 2015*

**physics**

M*g = 10kg * 9.8N/kg = 98 N. = Wt. of block. Fn = M*g - Fap*sinA = 98 - 75*sin37 = 52.9 N. Fk = u*Fn = 0.4 * 52.9 = 21.15 N. = Force of kinetic friction. a = (Fap*Cos37-Fk)/M = (75*Cos37-21.15)/10 =
*January 18, 2015*

**Math**

Rono: Cost = 4000 + 6*3000 = $22,000 Sam: Cost = 22000 - 5000 =
*January 17, 2015*

**Math**

Dan: Cost = 0.90 * 6245 = $5620.50 Dave: Cost = 3000 + 12*500 = $9,000 9000 - 5620.50 =
*January 17, 2015*

**Math**

Hali: Cost = 0.95 * 15000 = $14,250 John: Cost = 6000 + 3*3200 = $15,600 15,600 - 14,250 = $1,350 More than Hali.
*January 17, 2015*

**Physics**

V = 3km/h[90o] + 40km/h[20o] Y = 3 + 40*sin20 = 16.7km/h = Vertical or Northerly component. d = r*t = 16.7km/h * 6h = 100.1 km.
*January 17, 2015*

**physics**

See previous post: Sat,1-17-15, 6:18 PM.
*January 17, 2015*

**physics**

Power=Fx * d/t = 70.9*Cos48 * 19.9/4.3 = Note: J/s = Watts.
*January 17, 2015*

**physical science**

When they are acting in the same direction. Fmax = 5 + 7 = 12 N.
*January 17, 2015*

**Physics Class**

0.450 ms = 0.000450 s. V = Vo + a*t = -36.7 36.7 + a*0.000450 = -36.7 0.00045a = -36.7-36.7 = -73.4 a = -163,111 m/s^2 F = M*a = 0.140 * (-163111) = 22,836 N.
*January 16, 2015*

**Physics**

X = 1.84 m/s = Velocity of the current. Y = 1.1 m/s = Velocity of the boat. A. Vb^2 = X^2 + Y^2 = 1.84^2 + 1.1^2 = 4.60 Vb = 2.14 m/s. B. Tan A = Y/X = 1.1/1.84 = 0.59783 A = 30.9o, CCW = 59.1o E. of N. Tan59.1 = d/115 d = 115*Tan59.1 = 192 m. Downstream.
*January 16, 2015*

**Algebra**

a. Month 1: Profit = (4.31-1.50)/cup * 1283cups = $3605.23 Profit = (0.83-0.76)/donut * 216Donuts = $15.12 Month 2: Profit = (4.31-1.50)/cup * 4210cups = $11,830.10 Profit = (0.83-0.76)/donut * 317Donuts = $22.19
*January 15, 2015*

**physics**

V^2 = Vo^2 + 2g*h V = 0 g = -9.8 m/s^2 h = 6.57 m. Solve for Vo.
*January 15, 2015*

**Math**

(32 + 56) 32 = (1,32), (2,16), (4,8). 56 = (1,56), (2,28), (4,14), (7,8). CF = 1,2,4,and 8. GCF = 8. 8(4 + 7)
*January 15, 2015*

**physical science**

F(net) = F1 + F2 = 3.5 + (-4.5) = -1 N. = 1 N. Towards the Left.
*January 15, 2015*

**PHYSICS**

V^2 = Vo^2 + 2a*d = 0 d = -Vo^2/2a = -(25^2)/-5 = 125 m. Circumference = pi * 2r = 3.14 * 0.54 = 1.70 m. 125m * 1rev/1.70m = 73.5 Revolutions.
*January 15, 2015*

**physics**

See Related Questions: Tue, 9-10-13, 1:08 PM.
*January 15, 2015*

**math(5th grade)**

2.8pages/3.5min * 31.5min = 25.2 Pages.
*January 15, 2015*

**General/Academics**

Glad I could help.
*January 14, 2015*

**General/Academics**

0.75*85 + 0.25*F = 89 63.75 + 0.25F = 89 0.25F = 89-63.75 = 25.25 F = 101 = Finals score. Cannot be done! 0.75*85 + 0.25*100 = 88.75% = Max. possible score.
*January 14, 2015*

**physics**

Eq1:0.5M*V^2 = 198 J. Eq2: M*V = 13 M = 13/V In Eq1, replace M with 13/V: 0.5*(13/V)*V^2 = 198 6.5*V = 198 V = 30.5 m/s.
*January 13, 2015*

**Physics**

Vo = 1860m/s[67.4o] Xo = 1860*Cos67.4 = 714.8 m/s. Yo = 1860*sin67.4 = 1717.2 m/s. Y = Yo-g*Tr = 0 1717.2 - 9.8Tr = 0 9.8Tr = 1717.2 Tr = 175 s. = Rise time. Tf = Tr = 175 s. = Fall time Tr+Tf = 175 + 175 = 350 s. = 5.83 Min. in flight.
*January 13, 2015*

**Math**

Social studies: X Hours. 2 3/4 + 1 1/2 + x = 5 3/4 Hours. Solve for X.
*January 13, 2015*

**algebra**

-2(2+3)-2k = -2-4(2+2) -2(5)-2k = -2-4(4) -10-2k = -2-16 -10-2k = -18 -2k = -18+10 -2k = -8 Divide both sides by (-2): K = 4. 9(
*January 13, 2015*

**algebra**

Y = 16/20 * 38 = 30.4 in. = Length of short side. Cost = 6*Area = 6 * (38*30.4) = 20/16 = 38/30.4 = 1.25
*January 13, 2015*

**math**

Your Eq is correct. Length = X Ft. (2/5)x + 600 = 2000. Multiply both sides by 5/2: x + 1500 = 5000 X = 3500 Ft.
*January 12, 2015*

**physics**

F = 1500beats/30s = 50 Beats/s = 50cycles/s = 50 Hz. P = 1/F = 1/50 = 0.02 s.
*January 12, 2015*

**Physics**

Incomplete.
*January 12, 2015*

**physics**

Conservation of Linear Momentum: M1V1 + M2V2 = M1*V3 + M2*V3 M1 = 160,000 kg V1 = 0.30 m/s M2 = 115,000 kg V2 = -0.120 m/s Solve for V3, the final velocity.
*January 12, 2015*

**physics**

h = Vy*t + 0.5g*t^2 = 840 m. 0*t + 4.9t^2 = 840 Solve for t.
*January 12, 2015*

**physics**

Conservation of Linear Momentum: M1V1 + M2*V2 = M1V3 + M2*V4 77.5V1 + 21*0 = 77.5*2.18 + 21*2.18 77.5V1 + 0 = 214.73 V1 = 2.77 m/s.
*January 12, 2015*

**physics**

M1V1+M2V2 = 85*2 + 55*2.7[22o] = 170 + 148.5[22o] = 170 + 148.5*Cos22 + 148.5*sin22 = 170+137.7 + 55.63i = 307.7 + 55.63i = 313[10.25o] kg-m/s.
*January 12, 2015*

**Physics**

F = M*g = 0.55kg * 9.8N/kg = 5.39 N. K = 5.39N./0.36m = 14.97 N/m
*January 12, 2015*

**algebra--1 question**

Slope = (Y2-Y1)/(X2-X1)=(1+3)/(1+2)=4/3.
*January 12, 2015*

**Physic- help on direction (Not that good at Englis**

Use the slope that was calculated from your lab data to calculate g using the given equation.
*January 12, 2015*

**physics**

M*g = 89.7kg * 9.8N/kg = 879.1 N. = Wt. of box = Normal force(Fn). Fs = u*Fn = 0.5 * 879.1 = 439.5 N. = Force of static friction. Fap-Fs = M*a Fap-439.5 = M*0 = 0 Fap = 439.5 N. = Force applied.
*January 12, 2015*

**physics**

1. Draw a hor. line. 2. Draw a ver. line to the right-end of the hor. line and label it h for height. 3. From the left-end of the hor. line, draw a hypotenuse to the top of the ver. line. The angle it makes with the hor. is 12o. 4. Draw a 2nd hyp. to the right of the first and...
*January 12, 2015*

**physics**

E = 43 Volts. R1 = 13 Ohms R2 = 24 Ohms R3 = 41 Ohms I = I1 + I2 + I3 = E/R1 + E/R2 + E/R3 = 43/13 + 43/24 + 43/41 = 3.31 + 1.79 + 1.05 = 6.15 Amps. = Total current drawn from the 43-volt source. P = E*I = 43 * 6.15 = 264.5 Watts = Total power taken from the 43-volt source. P1...
*January 12, 2015*

**Physics-Check**

d1 = V1*T = 5m/s * 10min*60s/min=3000 m. d2 = V2*T = 4.5 * 10min*60s/min = 2700 m d1-d2 = 3000 - 2700=300 m. Between them. Or d=(5-4.5)m/s * 10min*60s./min=300 m. Between them.
*January 12, 2015*

**Mechanics**

Open circuit.
*January 11, 2015*

**math**

1 - 1/x = 2 - 2/x -1/x + 2/x = 1 1/x = 1 X = 1 3 - 3/x = 3 - 3/1 = 3 - 3 = 0
*January 11, 2015*

**physics**

V = Vo + a*t Vo = 2.5 m/s. a = 1.5 m/s^2 t = 4 s. Solve for V(m/s).
*January 11, 2015*

**Math**

P = Po*(1+r)^n Po = $4000 = Initial principal. r = (13.8%/12)/100% = 0.0115 = Monthly % rate expressed as a decimal. n = 12Comp/yr. * 4yrs. = 48 Compounding periods. Solve for Principal(P).
*January 11, 2015*

**Physics**

a. d = Circumference = pi*2r = 3.14 * 18.54 = 58.25 m. b. T = 1min/861rev = 60s/861rev = 0.0697 s./rev c. V=861rev/min * 58.25m/rev * 1min/60s =
*January 11, 2015*