Monday

April 27, 2015

April 27, 2015

Total # Posts: 10,494

**Physics**

First arrow: V = Vo + g*Tr = 0 Tr = -Vo/g = -10/-10 = 1.0 s.=Rise time So #2 is shot at the same time #1 starts falling. h = Vo*Tr - 0.5g*Tr^2 h = 10*1 - 5*1^2 = 5 m. ho-0.5g*t^2 = Vo*t + 0.5g*t^2 5 - 5*t^2 = 15*t - 5*t^2 5 - 5t^2 + 5t^2 = 15t The 5t^2 terms cancel: 15t = 5 t...
*April 26, 2015*

**PHYSICS ANSWER CHECK**

Vo = 60mi/h * 1600m/mi * 1h/3600s = 26.67 m/s V = Vo + a*t = 0 a = -Vo/t = -26.67/2.6 = -10.26 m/s^2 M = 3225Lbs * 0.454kg/1Lb = = 1464 kg F = M*a = 1464 * (-10.26) = -15,022 N. Note: Your answer would have been correct if you had converted 60 mph to m/s.
*April 25, 2015*

**PHYSICS answer check**

See previous post: Thu, 4-23-15, 6:12 PM.
*April 25, 2015*

**physics**

Rate of doing work = power. P = Fe*Cos21 * V P = 2.3*Cos21 * 7.9 = 17 J/s = 17 Watts.
*April 25, 2015*

**maths**

2 bags 6 Pouches Pouch cost $X each. Bag cost $(X+24) each. 2(x+24) + 6*x = $568 Solve for x.
*April 25, 2015*

**PHYSICS**

KE = 0.5M*V^2 = 0.5*0.025*80^2 = 80 J. F*d = F*1 = 80 J. F = 80 N.
*April 24, 2015*

**Math**

A(-8, 12), M(x, y), B(-13, -2) X = ((-8) + (-13))/2 = -10 1/2 = -21/2 Y = (12 + (-2))/2 = 5 M(-21/2, 5)
*April 24, 2015*

**physics**

Req = R1 + R2 + R3 = 13 + 35 + 2000 = 2048 Ohms.
*April 24, 2015*

**Algbra**

d1 = Sarah's distance d2 = Chelsea's distance. d2 = d1 + 55 Vc*T = Vs*T + 55 75T = 55T + 55 20T = 55 T = 2.75 h. = 2h-45 Min.
*April 24, 2015*

**physics**

See previous post: Thu, 4-23-15, 6:12 PM
*April 23, 2015*

**Physics**

a. KE = 0.5*M*Vo^2 KE = 200 J. M = 0.02 kg Solve for Vo, the initial velocity. b. M*g*h = 200 M = 0.02 kg 9 = 9.8 m/s^2 Solve for h.
*April 23, 2015*

**Physics**

Wt. = 0.05kg + 9.8N/kg = 0.49 N.
*April 23, 2015*

**Physics**

Y = Yo + g*Tr = 0 Yo - 9.8*(3.4/2) = 0 Yo = 16.66 m/s = Ver. component of initial velocity. sin A = Yo/Vo sin55 = 16.66/Vo Vo = 16.66/sin55 = 20.34 m/s Xo = Vo*Cos55 = 20.34*Cos55 = 11.67 m/s. V = Xo+Yi = 11.67 + 0 = 11.67 m/s Momentum change = M*V - M*Vo M = 3.0 kg V = 11.67 ...
*April 23, 2015*

**Math--Please help!!**

See previous post: Tue, 4-21-15, :31 PM.
*April 22, 2015*

**Consumer math**

1. 9 2/3 - 1/6=29/3-1/6=58/6 - 1/6=57/6 (57/6)/1/6 = 57/6 * 6/1 = 57 1.10 + 57*0.20 = $12.50 2. 9 - 1/6 = 54/6 = 1/6 = 53/6 1.10 + 53*0.20 = $11.70
*April 22, 2015*

**physics 111**

3. d = V*T = 40 km V*2 = 40 V = 20 km/h 4. Fr = 100N[170o] + 100N[50o] X = 100*Cos170 + 100*Cos50 = -34.2 N. Y = 100*sin170 + 100*sin50 = 94 N. Q2. Tan A = Y/X = 94/-34.2 = -2.74854 A = -70o = 70o N. of W. = 110o CCW Fr = Y/sin A = 94/sin110 = 5. Fap*CosA-Fk = M*a Fap = 40 N. ...
*April 22, 2015*

**physics**

Please read and clarify your problem. What is the vertical acceleration?
*April 22, 2015*

**physics 111**

1. V = Vo + g*Tr = 0 The rise time(Tr) = 1/2 of time in air. Vo = -g*Tr = 10(4/2)= 20 m/s
*April 22, 2015*

**PHYSICS**

Correction: Replace Tan A = Yo/Vo with sin A = Yo/Vo = 21.32/57.4 = 0.37143 A = 21.8o = Launch angle. a. Vo = 57.4m/s[21.8o] Xo = 57.4*Cos21.8 = 53.3 m/s = Hor. component of initial velocity. V = Xo+Yi = 53.3 + 0 = 53.3 m/s at highest point. KE = 0.5*M*V^2 = 0.5*0.0505*53.3^2...
*April 22, 2015*

**PHYSICS**

Y^2 = Yo^2 + 2g*h = 0 Yo^2 = -2g*h = -2*(-9.8)*23.2 = 454.72 Yo = 21.32 m/s = Ver. component of initial velocity. Tan A = Yo/Vo = 21.32/57.4 = 0.37150 A = 20.38o a. Vo = 57.4m/s[20.4o] Xo = 57.4*Cos20.4 = 53.8 m/s = Hor. component of initial velocity. V = Xo + Yi = 53.8 + 0 = ...
*April 22, 2015*

**Science**

F = 30kg/15kg * 5kg = 10 kg.
*April 21, 2015*

**math**

I = Po*r*t = 1100*(0.1/12)*1 = $9.17
*April 21, 2015*

**Personal Finance**

I chose C also.
*April 21, 2015*

**Algebra**

Y = 2x^2 - 7x - 2 h = Xv = -B/2A = 7/4. k = 2*(7/4)^2 - 7*7/4 - 2 = -8.125 = -8 1/8 = -65/8 P(h, k) = (7/4, -65/8).
*April 21, 2015*

**math**

P/3 = $3.00 P = Price.
*April 21, 2015*

**Geometry**

1. Correct 2. Correct 3. Correct!!! You aced it!!
*April 21, 2015*

**Pysics science**

8*Cos40 + 8*sin40 + B = 20 6.13 + 5.14i + B = 20 B = 20 - 6.13 - 5.14i B = 13.87 - 5.14i B = sqrt(13.87^2+5.14^2)
*April 21, 2015*

**Physics**

V^2 = Vo^2 + 2a*d V = 0 Vo = 50km/h = 50000m/3600s = 13.89 m/s d = 35 m. Solve for a. It will be negative.
*April 21, 2015*

**Math**

See previous post: Sun, 4-19-15, 7:26 PM
*April 20, 2015*

**Math**

Bracelet: 28/2 = 14 Green beads. Necklace: 56/4 = 14 Green beads.
*April 20, 2015*

**Physics**

d = 0.5*a*t^2 = 0.5*2*3.54^2 = 12.53 Rad
*April 20, 2015*

**MATH**

See previous post: Sun, 4-19-15, 7:26 PM.
*April 20, 2015*

**Physics**

Note: The Y component of the velocity decreases with time and is zero at the maximum height. The velocity increases as the stone falls. c. Dx = Xo*t = 13.91 * 1.76 = 24.48 m. d. Y = Yo + g*Tr = 0 12.35 - 9.8Tr = 0 9.8Tr = 12.35 Tr = 1.26 s. = Rise time or time to reach max ht...
*April 19, 2015*

**Physics**

Vo = 18.6m/s[41.6o] Xo = 18.6*Cos41.6 = 13.91 m/s Yo = 18.6*sin41.6 = 12.35 m/s a. X = Xo=13.91 m/s and does not change. Dx = Xo*t = 13.91 * 1.06 = 14.74 m. b. Y = Yo + g*t = 12.35 - 9.8*1.06 = 1.962 m/s h = Yo*t + 0.5g*t^2 Yo=12.35 m/s, t = 1.06 s, g=-9.8 m/s^2. Solve for h. ...
*April 19, 2015*

**physics**

M1*V1 + M2*V2 = M1*V + M2*V 11.2i - 18 = 4*V + 5*V = 9V V = -2 + 1.24i = 2.36m/s[31.9o] N. of W. = 2.36m/s[148.1o] CCW Momentum = M1*V + M2*V = 4*2.36[31.9] + 6*2.36[31.9] = 9.44[31.9] + 14.2[31.9o]=23.6m/s[31.9o] N. of W.
*April 19, 2015*

**Math**

I = Po*r*t = 875*(0.1425/12)*8 = $83.13
*April 19, 2015*

**science**

V = 60 mi/h * 1613m/mi * 1h/3600s = 26.9 m/s. V = Vo + a*t V = 26.9 m/s. Vo = 0 a = 2m/s^2 Solve for t.
*April 19, 2015*

**physics**

d = 110 - Vo*t = 110 - 20*0.7 = 96 m.
*April 19, 2015*

**algebra**

Multiply Eq2 by -4 and add Eq1 and Eq2: 2x + 4y + 2z = 144 -16x - 4y - 2z = -480 Sum: -14x = -336 X = 24 Multiply Eq1 by -2; add Eq1 and Eq3: -4x - 8y - 4z = -288 +x + 3y + 4z = 144 Sum: -3x - 5y = -144. X = 24. Solve for y: -3*24 - 5y = -144 -72 - 5y = -144 -5y = -144 + 72...
*April 18, 2015*

**science**

See previous post: Thu, 1-22-15, 12:20 AM.
*April 18, 2015*

**Algebra**

x = -1/3 x + 1/3 = 0 x = 3/7 x - 3/7 = 0 (x+1/3)(x-3/7) = 0 x^2 - 3x/7 + x/3 - 1/7 = 0 Multiply by 21: 21x^2 -9x + 7x - 3 = 0 21x^2 - 2x - 3 = 0
*April 17, 2015*

**Algebra**

Use same procedure as previous problem.
*April 17, 2015*

**Algebra**

x^2 - 2x + 2 = 0 X = (-B +- sqrt(B^2-4AC))/2A X = (2 +- sqrt(4-8))/2 X = (2 +- sqrt(-4))/2 X = (2 +- sqrt(4(-1))/2 X = (2 +- 2sqrt(-1)/2 X = (2 +- 2i)/2 = 1 +- i = 1+i, and 1-i. Check: (1+i)^2 - 2(1+i) + 2 = 1 + 2i - 1 - 2 -2i + 2 = 0
*April 17, 2015*

**Algebra**

(x+2)^2 + (x-7)(x-2) = 16 x^2 + 4x + 4 + x^2 - 2x -7x + 14 = 16 2x^2 - 5x + 18 = 16 2x^2 - 5x + 2 = 0 A*C = 2*2 = 4 = (-1)*(-4). Choose the pair of factors whose sum = B 2x^2 - (x+4x) +2 = 0 (2x^2-x) - (4x-2) = 0 x(2x-1) - 2(2x-1) = 0 (2x-1)(x-2) = 0 2x-1 = 0 2x = 1 X = 1/2 x-...
*April 17, 2015*

**Help with Psychology**

To help Karen overcome her fear of thunderstorms, a behavior therapist asks her to relax and imagine watching light rain with distant thunder. The therapist is using... a) client-centered therapy b) cognitive therapy c) systematic desensitization d) aversive conditioning ** ...
*April 17, 2015*

**Physics**

db = 10*Log W/Wo = 100 10*Log W/10^-12 = 100 Log W/10^-12 = 10 Log W - Log 10^-12 = 10 Log W = 10 + Log 10^-12 = 10-12 = -2 W = 10^-2 = 0.01 Watts.
*April 17, 2015*

**physics**

D = 5 + 10[30o] X = 5 + 10*Cos30 = 13.66 m. Y = 10*sin30 = 5 m. D = sqrt(X^2+Y^2) = sqrt(13.66^2 + 5^2) = 14.5 m.
*April 17, 2015*

**Math**

F = M*a = 0.04 * 2.5 = 0.1 N. a = F/M = 0.1/0.050 = 2.0 m/s^2
*April 16, 2015*

**exponential equations**

See previous post: Tue, 4-7-15, 7:04 AM.
*April 16, 2015*

**Physics**

h = 0.5g*t^2 g = 9.8 m/s^2. h = 0.75 m. Solve for t(Fall time). V^2 = Vo^2 + 2g*h Vo = 0 Solve for V. Dx = Xo*t Xo = 1.50 m/s t = Fall time. Solve for Dx
*April 16, 2015*

**math**

One Solution: Add to verify. -3x + 2y = 4 3x + 2y = 4 No Solution: Multiply Eq1 by (-1) and add. -3x + 2y = 4 -3x + 2y = 6 Infinite Solutions: Multiply Eq1 by 3 and compare. -3x + 2y = 4 -9x + 6y = 12
*April 16, 2015*

**College Physics**

See Related Questions: Thu, 8-26-14, 5:07 PM.
*April 16, 2015*

**math**

= 0.36603
*April 16, 2015*

**physics**

2nd Cable Direction = 30o E. of N.
*April 15, 2015*

**physics**

a = Fx/M = 15*Cos15/M
*April 15, 2015*

**physics**

V^2 = Vo^2 + 2a*d V = 0 Vo = 27 m/s d = 578 m. Solve for a. It will be negative. F = M*a
*April 15, 2015*

**physics**

M*g = 741 M = 741/g = 741/9.8 = 75.6 kg M*g = 5320 N. g = 5320/M = 5320/75.6 = 70.4 m/s^2
*April 15, 2015*

**Math**

Correction: You probably want the multiplication done without converting to base 10. I can't show it clearly here But it is long-hand multiplication. 1111 0101 0011110 0111100 1001011= Product = 75 base 10.
*April 15, 2015*

**Math**

1111 * 101 (1*2^3+1*2^2+1*2^1+1*2^0)*(1*2^2+0*2^1+1*2^0) = (8+4+2+1)*(4+0+1) = (15) * (5) = 75
*April 15, 2015*

**Physics**

a = F/M = 8/0.5 = 16 m/s^2 V^2 = Vo + 2a*d Vo = 0 a = 16 m/s^2 d = 4 m. Solve for V(m/s).
*April 15, 2015*

**math**

6*(1.2 * 1.2 * 1.2) = 6(1.2^3) = 10.37 in^3.
*April 15, 2015*

**angles**

ABD = ABC - DBC = 71 - 45 = 26
*April 15, 2015*

**Physics**

Vo = 7 m/s V = 3 m/s t = 8 s. V = Vo + a*t Solve for a. It should be negative. d = Vo*t + 0.5a*t^2 Solve for d.
*April 15, 2015*

**physics**

Wt. = M*g Newtons.
*April 15, 2015*

**Science**

Momentum = M*V
*April 14, 2015*

**Physics**

Y^2 = Yo^2 + 2g*h = 0 Yo^2 = -2g*h = -2*(-9.8)*10,000 = 196,000 Yo = 443 m/s.=Ver. component of initial velocity. Vo = Yo/sin60 = 443/sin60 = 512 m/s = Initial velocity = Speed at which the cannon is fired.
*April 14, 2015*

**math analysis**

Plane #1: d1 = 140mi/h[38o] * 2h = 280mi/h[38o] Plane #2: d2 = 180mi/h[350o] * 2h = 360mi[350] d = d2-d1 = 360[350o] - 280[38o] X = 360*Cos350 - 280*Cos38 = 134 mi Y = 360*sin350 - 280*sin38 = -235 mi D^2 = X^2 + Y^2 = 134^2 + (-235)^2 = 73,181 D = 270.5 Miles apart.
*April 14, 2015*

**Science**

1. Amplitude and wavelength. 4. Freq. 8. The freq. 9. To transmit signals.
*April 14, 2015*

**Physics**

See previous post: Sat, 4-11-15, 4:23 AM.
*April 14, 2015*

**physics**

Work = F*h = Mg*h = 400*9.8 * 60 = 235,200 J. = Output energy. Input energy = Output/Eff. = 235,200/0.8 = 294,000 J.
*April 14, 2015*

**Allegbra**

Use Quadratic Formula and get: 11.24
*April 13, 2015*

**Science**

For a given power output, the higher the voltage the lower the current. The lower current means less I^2*R loss. P = E*I = 100 * 10 = 1000 W. P = 1000 * 1 = 1000 W. Note: When E is increased to 1000 volts, the current is reduced to 1A.
*April 13, 2015*

**physics**

Fb = 80 kHz = Freq. emitted by the bat. Fh = 78 kHz = Freq. heard. Vs = 343 m/s = Velocity of sound in air. a. The bat is moving away. b. Fh = (Vs-Vr)/(Vs+Vb) * Fb = 78 kHz (343-0)/(343+Vb) * 80 = 78 Solve for Vb, the velocity of the bat.
*April 13, 2015*

**science**

M1*V1 + M2*V2 = M1*V + M2*V 40*2 + 4*0 = 40V + 4V 44V = 80 V = 1.82 m/s.
*April 13, 2015*

**Physics**

Incomplete.
*April 12, 2015*

**Maths help**

See previous post: Sat, 4-11-15, 4:23 AM.
*April 12, 2015*

**Maths help**

See previous post: Sat, 4-11-15, 4:24 AM.
*April 12, 2015*

**CIRCUIT**

E = 3 + 7 +V3 = 12 Solve for V3
*April 12, 2015*

**Physic**

P = 75 + 25 = 100 W., Total. P = 120 * I = 100 I = 100/120 = 0.833A R = E/I = 120/0.83333 = 144 Ohms.
*April 12, 2015*

**Physic**

See previous post: Thu, 4-9-15, 4:55 AM.
*April 12, 2015*

**Physic**

E = 120 V. R1 = 4.8k R2 = ? R1+R2 = 4(R1*R2)/(R1+R2) (R1+R2)^2 = 4(R1*R2) R1^2+2R1*R2+R2^2 = 4R1*R2 23.04+9.6R2+R2^2 = 19.2R2 R2^2 - 9.6R2 + 23.04 = 0 Use Quadratic formula R2 = 4.8k Check: Parallel Connection P1 = E^2/2.4k = 120^2/2.4k = 6,000 mW = 6 W. Series connection P2...
*April 12, 2015*

**Math, Circuits**

R1 = 3,000 Ohms = 3k Ohms R2 = 0.5k R3 = 10k I = 15 mA V1 = I*R1 = 15mA * 3k = 45 V.
*April 12, 2015*

**CIRCUITS**

Rt = R1+R2+R3 = 20k + 20k + 20k = 60k Ohms. = Total resistance. I = E/Rt = 120/60k = 2 mA(milliamps). V1 = V2 = V3 = I*R1 = 2 * 20k = 40 Volts Therefore, the voltage across each resistor is 40 Volts.
*April 12, 2015*

**Science**

M*g = 7 N. M = 7/g = 7/9.8 = 0.71 kg a = (Fap-Ff)/M = 1.4-1)/0.71=0.56 m/s^2 V = Vo + a*t = 0 + 0.56*4 = 2.24 m/s
*April 11, 2015*

**MATHSS**

Eq1: R1 + R2 = 1600 Ohms. Eq2: R2 = 2R1 - 560 Ohms. In Eq1, replace R2 with 2R1-560 R1 + 2R1-560 = 1600 3R1 = 2160 R1 = 720 Ohms In Eq1, replace R1 with 720 Ohms. 720 + R2 = 1600 R2 = 880 Ohms
*April 11, 2015*

**MATHSS**

Theta = 4 Rad. Wo = 3.2? Rad/s a = 0.6rad/s^2 Theta = Wo*t + 0.5a*t^2 = 4 rads. 3.2t + 0.5*0.6t^2 = 4 0.3t^2 + 3.2t - 4 = 0 Use Quadratic Formula. t = 1.13 s (Wo = 3.2 rad/s). t = 0.125 s (Wo = 32 rad/s).
*April 11, 2015*

**Mathematics**

Leslie: 4.5Laps/0.75h = 6 Laps/h Kala: 3.5Laps/0.75h = 4.67 Laps/h 6Laps/h - 4.67Laps/h = 1.33 Laps/h. Therefore, Leslie can run 1.33 more laps in 1 hr. than Kayla.
*April 10, 2015*

**PHYSICS**

Impulse = M*V = 3 * 2 = 6
*April 10, 2015*

**Physics**

Vr = 14 * pi*r^2 * h = 3.14*(0.295/2)^2 * 6.5 = 6.22 m^3 = Volume of the raft. Vr*Dr = 6.22m^3 * 600kg/m^3 = 3732 kg = Mass of the raft. Vw*Dw = 6.22m^3 * 1000kg/m^3 = 6220 kg = Mass of the water displaced. 6220 - 3732 = 2488 kg can be added to the raft. 2488kg * 1person/75kg...
*April 9, 2015*

**Maths**

a. X stamps, Total. 124 stamps, Australia 0.3x stamps, France 0.3x-12 stamps, Japan X = 124 + 0.3x + 0.3x-12 0.4x = 112 X = 280 b. 280 + n = 1.25*280 = 350 n = 70 Stamps from Lisa's aunt. (0.3x+n)/350 = (84+70)/350 = 0.44 = 44% from France.
*April 9, 2015*

**Physics**

a. Fr = 10N[60o]CCW + 15N[0o] X = 10*Cos60 + 15 = 20 N. Y = 10*sin60 = 8.7 N. Q1. Tan A = Y/X = 8.7/20 = 0.433 A = 23.4o N. of E. Fr = X/Cos A = 20/Cos23.4=21.8 N.[23.4o] N. of E. = 23.4o CCW b. Equilibrant: X = -20 Y = -8.7 Q3. Tan A = Y/X = -8.7/-20 = 0.433 A = 23.4o S. of W...
*April 9, 2015*

**Physic**

R1 = 1.4k Ohms R2 = 2.5k Ohms R3 = 3.7k Ohms P1 max = I1^2*R1 = 500 mW I1^2*1.4 = 500 I1^2 = 357.14 I1 = 18.9mA, max = Total current. Req. = R1 + (R2*R3)/(R2+R3) = 1.4 + (2.5*3.7)/(2.5+3.7) = 1.4 + 1.49 = 2.89k Ohms E max = I1*Req = 18.9 * 2.89 = 54.6 V. =
*April 9, 2015*

**math**

b. h = Vo*t + 0.5g*t^2 Vo = 192 Ft/s g = -32Ft/s^2 h = 432 Ft. Solve for t(Use Quadratic formula). c. h max = -(Vo^2)/2g = -(192^2)/-64 = 576 Ft. d. V = Vo + g*Tr = 0 Tr = -Vo/g = -192/-32 = 6 s. = Rise time Tf = Tr = 6 s. = Fall time. Tr+Tf = 6 + 6 = 12 s. to hit gnd.
*April 9, 2015*

**math**

h = Vo*t + 0.5g*t^2 Vo = 192Ft/s t = 10 s. g = -32Ft/s^2 Solve for h.
*April 9, 2015*

**Physics**

M*g = 330 * 9.8 = 3234 N. = Wt. of sled. Fp = 3234*sin6 = 38 N. = Force parallel to the incline. Fn = 3234*Cos6 = 3216 N. = Normal = Force perpendicular to the incline. Fk = u*Fn = 0.135 * 3216 = 434.2 N. = Force of kinetic friction. a = (Fap-Fk)/M = (1780-434)/330 = 4.08 m/s^...
*April 9, 2015*

**Physics**

Vo = 101km/h = 101,000m/3600s = 28.1 m/s = Initial velocity. See Related Questions: Tue, 10-28-14, 2:33 AM.
*April 9, 2015*

**math**

P = Po - Po*r*t = 11,090.41 120,000 - 120,000*r*12 = 11,090.41 -1,440,000r = 11,090.41 - 120,000 r = 0.0756 = 7.56% per annum
*April 8, 2015*

**Physics**

M*g = 59.9 * 9.8 = 587 N. = Wt. of girl and sled. Fp = 587*sin30 + 131 = 424.5 N. = Force parallel to the incline. Fn = 587*Cos30 = 508.4 N. = Normal = Force perpendicular to the incline. Fk = u*Fn = 0.217 * 508.4 = 110.3 N. = Force of kinetic friction. a=(Fp-Fk)/M = (424.5-...
*April 8, 2015*

**DPS PHYCIS**

Fr = 10[30] + 10[60o] X = 10*Cos30 + 10*Cos60 = 13.66 Units Y = 10*sin30 + 10*sin60 = 13.66 Units Fr = sqrt(X^2+Y^2)
*April 8, 2015*

**Physics**

Wavelength=V*P = V*(1/F) = V*(1/3.8) = 0.48 m. V/3.8 = 0.48 V = 1.82 m/s
*April 8, 2015*