Thursday

October 23, 2014

October 23, 2014

Total # Posts: 9,329

**Physics**

Xo = 6 m/s. Yo = 3.5 m/s. a. tanA = Yo/Xo = 3.5/6 = 0.58333 A = 30.3o Vo=Xo/cosA = 6/cos30.3 = 6.95m/s[30.3o] b. X = Xo = 6 m/s. It does not change. c. Y = Yo + g*t Y = 3.5 - 9.8*0.5 = -1.4 m/s. The negative sign means the ball is falling. d. h=(Y^2-Yo^2)/2g=(0-3.5^2)/-19.6 = ...
*November 7, 2013*

**physics**

F = 10*4^2 + 100 = 260 N. Wc = m*g = 25 * 9.8 = 245 N. = Wt. of crate. Fk = uk*mg = 0.25 * 245 = 61.25 N. = Force of kinetic friction. a = Fn/m = (F-Fk)/m = (260-61.25)/25 = 7.95 m/s^2. V = a * t = 7.95 * 4 = 31.8 m/s.
*November 7, 2013*

**Physics**

a. C = pi*2r = 3.14 * 3 = 9.42 m. V = (20/9.42) * 2pi = 4.25pi rad/s = 13.34 rad/s.
*November 7, 2013*

**Physics**

V = a*t = 1.7 * 0.7 = 1.19 m/s.
*November 7, 2013*

**physics**

Vo = 5.8m/s[17o] Xo = 5.8*cos17 = 5.55 m/s. Yo = 5.8*sin17 = 1.70 m/s. Y = Yo + g*t = 0 @ max. ht. Tr = (Y-Yo)/g = (0-1.70)/-9.8 = 0.173 s. = Rise time. h=(Y^2-Yo^2)/2g = (0-1.7^2)/-19.6=0.147 m. h = 1.4 + 0.147 = 1.55 m Above shorter bldg. h = 0.5g*t^2 = 1.55 m. 4.9*t^2 = 1....
*November 7, 2013*

**Physics**

Fap - 0.6*34 = m*a = m*0 = 0 Fap = 20.4N,mln. = Force applied. 27,2 N will move the block. m*g = 34 m*9.8 = 34 m = 3.47 kg a=Fn/m = (27.2-0.472*34)/3.47=3.21 m/s^2
*November 7, 2013*

**science**

11 - L = (150/100)*(9-L) 11-L = 13.5 - 1.5L 0.5x = 2.5 L = 5 cm
*November 7, 2013*

**MATHS**

Mass = 2*(200+(3/5)*200) = 640 Grams.
*November 7, 2013*

**physics**

d = V * t = 343m/s * 0.5s = 171.5 m.
*November 6, 2013*

**maths**

X = # short sticks. 2X = # Long sticks. x + 2x = 45 X = 15 Short sticks. 2X = 30 Long sticks. Therefore, you can make 15 triangles using 15 short sticks and 30 Long sticks. If the answer was 11 triangles: 11triangles * 3sticks/triangle = 33 sticks.
*November 6, 2013*

**physics**

Va=23rev/2.8min * 2pirad/rev * 1min/60s= 0.274 rad/s.
*November 5, 2013*

**physics**

C = pi * D = 3.14 * 100 = 314 m. = The Circumference. d = 14m/s * 240s = 3360 m Da = (3360/314) * 2pi Rad. = 21.4pi Rad.
*November 5, 2013*

**Physics**

V=60mi/h * 1600m/mi*1h/3600s.=26.67m/s d2 = d1 + 20 m Vo*t + 0.5a*t^2 = V1*t + 20 26.67*2 + 0.5a*2^2 = 26.67*2 + 20 53.33 + 2a = 73.33 2a = 20 a = 10 m/s^2.
*November 5, 2013*

**physics**

h = Vo*t + 0.5g*t^2 = 1000 m. 10t + 4.9t^2 - 1000 = 0 Use Quadratic Formula and get: t = 13.3 s.
*November 5, 2013*

**Physics**

Dx = Xo * Tf = 35 m. 22.2 * Tf = 35 Tf = 1.577 s. = Fall time. h = 0.5g*Tf^2
*November 4, 2013*

**Math**

d1 = 23.5mi/h * 2h = 47 Mi[180o-32.1o] = 47Mi[147.9o] d2 = 23.5mi/h * 1h = 23.5mi[180-53.6] = 23.5mi[126.4o] d1 + d2 = 47mi[147.9] + 23.5mi[126.4o] X = 47*cos147.9 + 23.5*cos126.4=-53.8 mi Y = 47*sin147.9 + 23.5*sin126.4=43.9 mi D^2=X^2 + Y^2=-53.8^2 + 43.9^2=4821.65 D = 69.4 ...
*November 4, 2013*

**Math**

Y = (-1/2)x + 2.
*November 4, 2013*

**college Algebra**

Ln y = -0.35 Exponential form: e^(-0.35) = Y Y = 0.7047
*November 4, 2013*

**college Algebra**

post
*November 4, 2013*

**college Algebra**

Ln y = Log 9 = 0.95424 Exponential form: e^(0.95424) = y Y = 2.5967
*November 4, 2013*

**Math**

X = # of children's tickets sold. Y = # of adult tickets sold. 30x + 40y = 930 Replace Y with 0: 30x + 40*0 = 930 X = 31 = X-Int. Replace X with 0: 30*0 + 40y = 930 Y = 23.25 = Y-Int.
*November 4, 2013*

**physics**

KE + PE = 480 Joules 220 + PE = 480 PE = PE = 260 J. mg*h = 260 34*9.8*h = 260 333.2h = 260 h = 0.780 m.
*November 4, 2013*

**Physics**

Correction: See your 10:57 PM post.
*November 3, 2013*

**Physics**

See your 11:57 PM post.
*November 3, 2013*

**Physics**

See your 11:57 PM post.
*November 3, 2013*

**Physics**

See your 10:57 PM post.
*November 3, 2013*

**Physics**

V = Vo + g*t = 0 at max. h. 4.6 - 9.8t = 0
*November 3, 2013*

**Physics**

X + Y = 365 X - Y = -123 Sum: 2x = 233 X = 116.5 N. X + Y = 365 116.5 + Y = 365 Y = 248.5 N.
*November 3, 2013*

**5TH GRADE Math**

1. 1 = 1*1. 4 = 1*2*2 8 = 1*2*2*2. 32 = 1*2*2*2*2*2. The common factor is 1. 2. 1 = 1*1 3 = 1*3. 6 = 1*2*3. 12 = 1*2*2*3 24 = 1*2*2*2*3. The common factor is 1. the commonfactors are 1,and 3.
*November 3, 2013*

**Physics**

V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*(53-14) = 764.4 V = 27.65 m/s at 14 m above gnd. h = Vo*t + 0.5g*t^2 = 14-2 = 12 27.65t + 0.5g*t^2 = 12 4.9t^2 + 27.65t - 12 = 0 Use Quadratic Formula and get: t = 0.405 s. To get out of the way.
*November 3, 2013*

**science**

V1=60mi/h * 1600m/ml * 1h/3600s=26.7m/s Vo = (50/60) * 26.7m/s = 22.22 m/s. a = (V1-0)/t = (26.7-0)/8 = 3.33 m/s^2 V = Vo + a*t = 22.22 + 3.33*5=38.87 m/s = Final speed.
*November 3, 2013*

**Finance**

B. Tuition and dorm fees.
*November 3, 2013*

**science**

Wt. = V * Dw Wt. = 450cm^3 * 1g/cm^3 = 450 g = Max. wt. without sinking. 14.5 + X = 450 Grams. X = 435.5 grams can be added. 435.5/2.5 = 174.2 or 174 Pennies.
*November 3, 2013*

**Physics**

Vr = (11m/s)/cos(90-55) = 13.4 m/s.
*November 3, 2013*

**electronics**

True.
*November 3, 2013*

**pen state university**

d = 0.5a*t^2 = 42 rad. 0.5*0.025*t^2 = 42
*November 3, 2013*

**Physics**

See previous post.
*November 3, 2013*

**Physics**

W = F * d = 9.55*10^-3 * 8.6*10^-2= 82.13*10^-5 = 8.21*10^-4 Joules.
*November 3, 2013*

**Physics**

Fg = m*g = 20kg * 9.8N/kg = 196 N. Fp = 196*sin40 = 126 N. = Force parallel to incline. Fn = 196*cos40 = 150 N. = Normal. h = L*sin40 = 6.5*sin40 = 4.18 m. Wg = Fg * h = 196 * 4.18 = 819.3 Joules. Wn = = Fn * h = 150 * 4.18 = 628 N. Fp-Ff = m*a = m*0 = 0 126-Ff = 0 Ff = 126 N...
*November 2, 2013*

**Physics**

a. Fr^2 = 119.7^2 + 49.9^2 = 16,818.1 Fr = 129.7 N. b. tanA = Y/X = 49.9/119.7 = 0.41688 A = 22.63o = Direction.
*November 2, 2013*

**Physics**

a. V = a*t = 8 m/s a*5 = 8 a = 1.6 m/s^2. b. d = 0.5a*t^2
*November 2, 2013*

**Physics**

V = a * t = 1.5[60] * 15 = 22.5m/s[60o. X = 22.5*cos60 = 11.25 m/s = Easterly component. Y = 22.5*sin60 = 19.49 m/s = Northerly component.
*November 2, 2013*

**Physics**

a. h = 0,5g*t^2 = 4.9*2.5^2 = 30.6 m. b. d = V * t = 50 m. V*2.5 = 50 V = 20 m/s.
*November 2, 2013*

**physics**

Increase in L = a*(T-To)L = 10cm = 0.1m 11.8*10^-6/oC(T-0)1000 = 0.1 0.0118T = 0.1 T = 8.47o C
*November 1, 2013*

**Physics**

See previous post.
*November 1, 2013*

**Physics**

See previous post: Fri,11-1-13,9:21 AM.
*November 1, 2013*

**Physics**

Vo = 22m/s[55o] Xo = 22*cos55 = 12.62 m/s. Yo = 22*sin55 = 18.02 m/s. h = Yo*t + 0.5g*t^2 h = 18.02*2 - 4.9*2^2 Y = = Yo + g*t 18.02 - 9.8*2 = -1.58 m/s. = Vertical component of velocity. The negative sign means the rock is falling.
*November 1, 2013*

**Physics problem**

See previous post: Fri,11-1-13,1:00 AM.
*November 1, 2013*

**Physics problem**

A.h = Vo*t + 0.5g*t^2 = 80 0 + 4.9t^2 = 80 B. V^2 = Vo^2 + 2g*h V^2 = 0 + 19.6*80 = 1568 V = 39.6 m/s. C.
*November 1, 2013*

**science**

V = Vo + a*t. a = Fn/m = 4.8*10^5/4.8 = 1*10^5 m/s^2. t=(V-Vo)/a = (3900-0)/1*10^5 = 0.039 s.
*November 1, 2013*

**algebra solving log equations**

Ln sqrt(x-8) = 5 Exponential form: e^5 = sqrt(x-8) Square both sides: e^10 = x-8 X = 8 + e^10 exponential form:
*October 30, 2013*

**geometry**

C(-3,-1), P(-3,2). r = 2 - (-1) = 3.
*October 30, 2013*

**alGEBRA 2 help please would appreciate**

CORRECTION: F(X1,0), V(0,0), D(X2,0).
*October 30, 2013*

**alGEBRA 2 help please would appreciate**

-4x-8y^2 = 0 -4x = 8y^2 X = -2y^2 This is an X-parabola; it opens to the left because "a" is negative. K = -b/2a = 0/-4 = 0 h = 0^2 = 0 V(h,K) = V(0,0). D(X1,0), V(0,0), F(X2,0). X1 = h - |1/4a| = 0 - 1/8 = -1/8. X2 = h + |1/4a| = 0 + 1/8 = 1/8. Use the following ...
*October 30, 2013*

**Science**

F = m*a
*October 29, 2013*

**Geometry**

tanA = h/X tan68o = h/50 Solve for h.
*October 29, 2013*

**Physics**

A. X = 36 m/s. Y = 21 m/s. V^2 = X^2 + Y^2 = V^2 = 36^2 + 21^2 = 1737 V = 41.7 m/s. Impulse = m*V = 0.23 * 41.7 = 9.59 B. tan A = Y/X = 21/36 = 0.58333 A = 30.3o = Direction.
*October 29, 2013*

**physics**

d2 = d1 0.5a*t^2 = V1*t 1.43*t^2 = 20.2t 1.43t^2 - 20.2t = 0 Use Quadratic formula. t = 14.1 s.
*October 29, 2013*

**Math**

1. D. 2. A. 6. A. 8. Cost = 1.06(10,150+738+50) = 9. B. 10. D. 11. Cost(8,250+324+50) = 12. Value = (1-0.48)*28,000 = 18. B. 19. Same procedure as #12. 20. B. IRA
*October 29, 2013*

**Algebra 1---Urgent! Please, help me!**

1. P =< 14-9 P =< 5. 2. (4/5)h => -2 Multiply both sides by 5/4: h = > -10/4 h => -5/2 or 2.5 3. S = 115/12 = 9 Shirts and 7 Buttons left over.
*October 28, 2013*

**Math**

a. d = (6688/1760) * 1mi = 3.8 Mi. b. 3.8mi * 5,280Ft/mi = 20,064 Ft.
*October 28, 2013*

**Physics**

tan A = Y/X = 6/16 = 0.375 A = 20.56o
*October 27, 2013*

**finacne**

c. P = Po + Po*r*t P = 75,000 + 75000*0.05*15 = $131,250.
*October 27, 2013*

**Physics**

See previous post.
*October 27, 2013*

**Physics**

Vo = a*t = 28.4*4.79 = 136 m/s. h = Vo*t + 0.5g*t^2 h = 136*4.79 - 4.9*4.79^2 = 539 m.
*October 27, 2013*

**Physics**

a. V^2 = Vo^2 + 2g*h V^2 = 0 + 20*1.6 = 32 V = 5.66 m/s. = Final velocity before striking the gnd. Vo^2 = V^2 - 2g*h Vo^2 = 0 - 20*0.9 = 18 Vo = 4.24 m/s = Velocity at which it leaves the gnd. Energy Lost=0.5m*V^2-0.5m*Vo^2 = 0.02*5.66^2 - 0.02*4.24^2=0.281 Joules b. Vo = 4.24...
*October 27, 2013*

**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*

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