Thursday

March 5, 2015

March 5, 2015

Total # Posts: 2,070

**Physics**

w = 2*pi*f f = 1/19.9 where f is the frequency of the car going around the track, w is the angular speed around the track, pi is 3.14 w = 2*pi/19.9 =0.315 The speed traveled by one tire is w*r where r is the radius of the wheel The speed traveled by the other tire is w*(r+1.63...
*October 28, 2012*

**chemistry**

PV = nRT where P = pressure, V = volume, R is a constant = 8.314 J/mol*K, and T is temperature in degrees Kelvin, n is number of moles degrees K = 273 + degrees C 1 liter = 1000 cm^3 = 1000 cm^3* (1 m / 100 cm)^3 = 1000 * (1/1000000) = 1/1000 = 0.001 m^3 35 L = 0.0035 m^3 P*0....
*October 27, 2012*

**Math**

Change 30/20 into a mixed number
*October 25, 2012*

**Math**

8/12=
*October 25, 2012*

**Math**

How much larger is the 8 in 657,689,004 than the 8 in 789,456,234?
*October 25, 2012*

**english**

Direct characterization The author literally tells the audience what a character is like. This may be done via the narrator, another character or by the character him- or herself. Indirect characterization The audience must infer for themselves what the character is like ...
*October 25, 2012*

**math**

e^(ln(5-2x)) = e^3 5-2x = e^3 5-e^3=2x x = (5-e^3)/2
*October 25, 2012*

**physics**

The lift force L has an x and y component Lx and Ly: Lx = Lsin21 Ly = Lcos21 In the y direction, Lcos21 - 55600 = 0 Solve for L In the x direction Lsin21 - Fair = 0 where F air is the force of air resistance
*October 25, 2012*

**Physics!**

The first rope has an x component of force Fx1 and a y component of force Fy1: Fx1 = 57*sin 30 = 28.5 Fy1 = 57*cos 30 = 49.3 The second rope has an x component of force Fx2 and a y component of force Fy2: Fx2 = 57*sin 60 = 49.3 Fy2 = 57*cos 60 = 28.5 The net force in the x ...
*October 25, 2012*

**Math**

Ned caught 1/3 pound of fish. Sarah caught 5/12 pound of fish . Jessica caught 1/6 pound of fish. How much fish did all three of them catch?
*October 24, 2012*

**Math**

How much larger is the 6 in 657,879,004 than the 6 in 789,456,234?
*October 24, 2012*

**Math**

There are 10 tennis balls, 2 soccer balls, and 8 basketballs. What fraction in simplest form are tennis balls?
*October 24, 2012*

**Geometry**

Use the corresponding angles converse: If two lines are cut by a transversal and the corresponding angles are congruent, the lines are parallel. The transversal line is along the side of the ship parallel to the water, and the angles of the oars with the water are all ...
*October 24, 2012*

**Physics**

When it has stretched from its maximum position, the potential energy stored in the spring is 1/2*k*x^2 = 1/2*450*.5^2 = 56.25 this is converted to kinetic energy: 56.25 = 1/2*m*v^2 = 1/2*8*v^2 Solve for v
*October 24, 2012*

**math**

The twelve 1" cubes divided by /3 layers give 4 cubes/layer The shape is four layers of squares, 4 cubes on a side, or a cube with dimensions 4*4*4 cubes.
*October 24, 2012*

**Algrbra**

if 0≤x≤ 10000 : R(x) = $12 * 11% *x at x = 10000, R(x) = $12 * 11% *10000 = 13200 10000 < x ≤ 15000 : R(x) = 13200 + $12*12.5%*(x-10000) (The profit made on the first 10000 books + the profit made on books sold above 10000) at x = 15000, R(15000) = 13200...
*October 24, 2012*

**math 7 grade**

1*ch1 + 9*ch2 + 81*ch3 = 200 with ch1+ch2+ch3 <= 8 where ch1 is the number of charities belonging to the first group, ch2 is the number of charities belonging to the second group, and ch3 is the number of charities belonging to the 3rd group the number in charity 3 can only...
*October 24, 2012*

**Finance**

5000 * (1+x)^7 = 38700 Solve for x
*October 24, 2012*

**algebra 1**

Enter these data points into some graphing software, and ask the computer to perform a linear regression on the data (find the best-fit line that goes through the data points) The computer should also be able to calculate the correlation coefficient. If the correlation ...
*October 24, 2012*

**physics**

450 = m*v^2 / r where m is mass, v is speed, and r is radius
*October 24, 2012*

**pre-cal**

The initial velocity is in the y-direction. A) It's height above ground is y = x0 + v0*t - 1/2*g*t^2 where y is its height, x0 is its initial position, v0 is it's initial speed in the y direction, g is the acceleration due to gravity and t is time. Plugging in the ...
*October 24, 2012*

**physics**

the centripetal acceleration is omega^2*r where omega is the angular velocity, and r is the radius at that point 118 m/s^2 = omega^2*0.382 solve for omega, then find a : a = omega^2 * 0.0791
*October 24, 2012*

**physics**

1 hr = 60 min * 60 sec/min = 3600 s 73.2 s = 73.2 s / (3600 s/h) = 0.0233 hr 4mi / 0.0233 hr = 196.7 mi/h
*October 23, 2012*

**math**

There are 6 combinations for the first dice, and 6 combinations for the second dice, so the total number of possibilities is 36 There are only 4 ways to get a sum of 9: (4,5), (5,4), (3, 6), (6, 3) There are only 3 ways to get 4: (2, 2), (1,3), (3,1) There are only 5 ways to ...
*October 23, 2012*

**Physics**

For two lenses: 1/f = 1/f1 + 1/f2 where f is the focal length of the lens combination, f1 is the focal length of the first lens, and f2 is the focal length of the 2nd lens Extending this to 4 lenses: 1/f = 1/f1 + 1/f2 + 1/f3 + 1/f4 or 1/f = 1/200 - 1/125 -1/400 + 1/142.9 1/f...
*October 23, 2012*

**Calc**

a) First: the definition of a tangent line is defined as a line passing through a given point of a function whose slope is equal to the derivative of the function at that point The equation of the tangent line is of the form y = mx + b, where m is the slope, and b is the y-...
*October 23, 2012*

**Science**

The metric unit of distance is meters; The metric unit of time is seconds; The metric unit of speed is meters/second The units of distance and time are unrelated; the units of speed are defined in terms of metrical units of distance and time, or the rate of change of distance ...
*October 23, 2012*

**Physics**

w = w0 + a*t theta = w0*t + 1/2*a*t^2 where w is the angular speed, w0 is the initial angular speed, and a is the angular acceleration, and theta is the angle turned in radians, so 3.14*10^4 = 1.2*10^4 + a *t 1.92*10^4 = 1.2*10^4*t + .5*a*t^2 Solve this system of equations ...
*October 23, 2012*

**Physics**

Is this a trick question? The problem states that the mass of Puck A is 0.025 kg, and the mass of puck B is 0.060 kg. The collision does not change the masses, only the velocities
*October 23, 2012*

**Physical Science**

I don't think so, because if you can find a derivation for the buoyant force you will see that it depends on the fact that the pressure of a liquid increases with depth.
*October 23, 2012*

**Physics**

m*a = Liftforce - m*g In this case m is the combined mass of the helicopter and frame, so 9000*0.9 = Liftforce - 9000*g Solve for lift force B) Drawing a free body diagram on the frame: T - mg = m*a T - 1100*9.8 = 1100*0.9 Solve for T C) Drawing a free body diagram on the ...
*October 23, 2012*

**CHEMISTRY**

the heat capacities are given in units of moles and Kelvins, so you'll have to convert everything to these units The weight of one mole of H2O = 1.008*2 + 15.999 = 18.015 g 17.68 g ice = 17.68g * (1 m / 18.015 g ) = .981 moles ice = .981 mole H20 54.05 g water = 3 moles ...
*October 23, 2012*

**history 103**

Summarize the major factors that allowed the Incas to conquer and rule their large empire. Some suggest that, in many ways, the Incas were like the Romans or other Pre-Columbian American Civilizations. Evaluate whether they were more similar or different, and why. Make sure to...
*October 22, 2012*

**statistics**

0.5
*October 19, 2012*

**math**

Without the pass, the rider pays 2.00 * T With the pass the rider pays 17.25 + 1.25*T Set the two equal to each other, and solve for T 2.00 * T = 17.25 + 1.25 * T where T is the number of tickets
*October 17, 2012*

**Math**

S = 0.06(200,000 - 0.30(200,000 - S)) Start multiplying S = 0.06(200,000 - 60000 + 0.3*S) S = 12000 - 3600 + 0.018*S 0.982*S = 8400 S = 8554 F = 0.3(200000-8554) Solve for F
*October 17, 2012*

**physics**

The dimensions are irrelevant. F = m*g = 0.77 * 9.8
*October 17, 2012*

**Math**

(66 + 66 + 66 + x) / 4 = 70 Solve for x
*October 17, 2012*

**Math**

Each side will be multiplied by 1.25, so the total perimeter will be multiplied by 1.25 20*1.25 =
*October 17, 2012*

**Math**

(73.5 + 73.5 + x )/3 = 75 Solve for x
*October 17, 2012*

**math**

All three numbers must be factors of 60; 8 is not a factor of 60 so it can be excluded. The numbers left are 2, 4, 5, 6 You must take the three greatest to get a sum of 15: 4+5+6 = 15 and 60 is the GCF of 4, 5, 6
*October 17, 2012*

**Math**

Sven's equation tells him how many dollars he spent per yo-yo.
*October 17, 2012*

**math**

Let P be the number of pennies, D be the number of dimes, Q be the number of quarters, and N the number of nickels (if N is 0, we will discover it when we solve the system of equations) P + D + Q + N = 8 P = 2*D D = 2*Q P + 10*D + 25*Q < 95 Q can only be only 1, otherwise P...
*October 17, 2012*

**Math**

P = 225 * 1.1^t Explanation: Every year, the population grows by 10%, so you multiply by 110% for the first year, 110%*110% for the second year, etc. Evaluate y=6000e−x/20 at x = 20 and at x = 120 y(20)=6000e−20/20 = 6000 * e^-1 = 2207 y(120)=6000e−120/20 = ...
*October 17, 2012*

**4th grade algebra**

C = 3*L - 1 C + L = 25 where C is the number of bottles Christina has, and L is the number that Lucia has Use algebra to solve
*October 17, 2012*

**health**

I would think D--None of the conditions listed would necessarily prevent anyone from doing at least certain types of resistance exercises.
*October 17, 2012*

**algebrsa**

0=vy*5.39-.5*9.8*t or vy*5.39 = 0.5*9.8*t vy = (0.5*9.8*t)/5.39
*October 17, 2012*

**math 5**

Estimate the volume of one penny, but you should probably estimate the size of a small box that a penny would fit into, because when you shove pennies into a box, there's a lot of empty space between the pennies that can't be filled. The volume of the space occupied by...
*October 17, 2012*

**Math**

I would start making a chart, for Artie, his next shopping days are 5, 10, 15, 20, 25, 30,. . . days after Tuesday for Tom, his next shopping days are 4, 8, 12, 16, 20, 24, The first time they meet is the GCF of 4, and 5, or 20 days after Tuesday. The day of the week is ...
*October 17, 2012*

**physics**

x = 1/2 * g * t^2 22.5 = 0.5 * 9.8 * t^2 Solve for the time
*October 17, 2012*

**ALG 2!!!**

Use your calculator 5^2 = 5*5 = 25 25 - 16 + 25 = 50 - 16 =
*October 17, 2012*

**math 7**

In the US, 2000 pounds are in one ton. One quarter ton is 0.25 * 2000
*October 17, 2012*

**Business Math**

13 1/2 % = 13.5% = 0.135 monthly commission = 0.135 * 4230
*October 17, 2012*

**geography**

Precipitation is a type of moisture that naturally falls to the ground as part of a weather pattern, so snow, rain and hail
*October 17, 2012*

**physics**

The momentum of the first ball is 4*15 kg m/s This is equal to the momentum of the 14 kg ball after it starts moving: 4*15 = 14*v where v is the velocity of the second ball
*October 17, 2012*

**Math**

The first two numbers are the length and width of the garden, and in every case, they add up to 188; The third number is the area. The one with the greatest area is C. (94 * 94 = 8836)
*October 17, 2012*

**Math**

a^2 = b^2 + c^2 - 2bc cosA b^2 = a^2 + c^2 - 2ac cosB c^2 = b^2 + a^2 - 2ba cosC where a, b, and c are the sides of the triangle, and A, B, C are the angles opposite the sides. Plug a, b, c = 3, 5, 7 into these equations and solve for the angles A, B, C. The smallest of these ...
*October 17, 2012*

**Physics IB**

The sum of the initial momentums is equal to the sum of the final momentums: m*5 - m*7 = m*v1f + m*v2f The sum of the initial kinetic energy is equal to the sum of the final kinetic energy: 0.5*m*5^2 + 0.5*m*7^2 = 0.5*m*v1f^2 + 0.5*m*v2f^2 where v1f is the final speed of ball ...
*October 17, 2012*

**Calculus II**

3^0.5 = 1.732 5^0.5 = 2.236 on [3,5], 3^x - 1.732 < 0.01 5^x - 2.236 < 0.01 3^x < 3^0.5 + 0.01 x < log(3) (1.742) 5^x < 5^0.5 + 0.01 x < log(5) (2.246) For the first equation, x < 0.50521360825 For the second equation, x < 0.50275369436 x has to be ...
*October 17, 2012*

**physics**

It is the total distance traveled in the y direction between these two times, divided by the difference in times: (y(t=0.3) - y(t=0.2)) / (0.3-0.2)
*October 17, 2012*

**PHYICS**

x = vx*t y = vy*t - 0.5*9.8*t^2 Assuming it hits the ground at 5.39 seconds: 66 = vx*5.39 0 = vy * 5.39 - 0.5*9.8*5.39^2 Where vx is the speed in the x direction, vy is the speed in the y direction. The magnitude of the speed is (vx^2 + vy^2)^0.5 The direction of the speed is ...
*October 17, 2012*

**math**

a) Plug in x = 1071, and x = 1891 into the equation C(x) to find the actual cost at these values. b) The marginal cost is the cost of producing one more extra good, so the marginal cost when x = 1070 is C(x=1071) - C(x=1070) for 1890 it is C(x=1891) - C(x=1890)
*October 17, 2012*

**grammar**

Valdezes' This would refer to something that belongs to the Valdez family
*October 17, 2012*

**math**

An integer is defined as any whole number from -infinity to infinity. Therefore, there are three cases 1. The integer is 0 2. The integer is positive 3. The integer is negative 1. If the integer is zero, zero * zero is zero, which is not negative. 2. If the integer is positive...
*October 17, 2012*

**Math**

There a total of 12 face cards in a stack of 52 playing cards. You know that the second card is an ace, so the value of 51 cards are unknown. Therefore, the probability is 12/51
*October 17, 2012*

**Math**

There are 13 spades in a deck of cards. You know the suit of the second card, so the suit of 51 cards is unknown. The probability is 13/51
*October 17, 2012*

**math**

1 nickel = $0.05 $0.05 / $1.00 = 0.05 = 5%
*October 17, 2012*

**Math**

H+(conc) = 10^-pH So, in the first case, H+ = 10^-4 in the second case, the concentration of H+ = 10^-8 Subtract these two to find the difference, or divide the two to find a ratio expressing the change. A pH below 7 is acidic, a pH above 7 is basic, so increasing pH means the...
*October 17, 2012*

**CHEMISTRY**

NH4OH breaks down into NH3 and H2O
*October 17, 2012*

**Maths**

GB = 8*G BB = 3*B GB - BB = 46 Where GB is the number of girl's books, BB is the number of boy's books, G is the number of girls, and B is the number of boys. Use algebra to solve this system of equations 2nd problem B/G = 2/3 G(glasses) + G(noglasses) = G G(glasses)/G...
*October 17, 2012*

**Calculus**

a square is defined by the unit vectors i(vector) and j(vector). FInd the projections of i(vector) and j(vector) on each of the diagonals of the square.
*October 15, 2012*

**Chemistry**

Which of the following is a negative ion? Na+1,Na,O-2,O? All of them?
*October 7, 2012*

**Chemistry**

Which of the following molecules has the highest boiling point? CH4,BH3,NH3, SH2?
*October 7, 2012*

**c programming**

Read the four steps of the software development procedure in Section 1.7. If you understand it, you should be able to answer the problem
*October 5, 2012*

**Chem**

the molar mass of KMnO4 is 39.098 + 54.938 + 15.999*4 = 158.032 200 ml = 200 mL / 1000 mL/L = 0.2 L 0.2 L * 0.3 moles/L = 0.06 Moles KMnO4 = 0.06 * 158.032 g/mol = 9.48 g KMnO4
*October 5, 2012*

**Physics**

vx(t) = vx0 vy(t) = vy0 - g*t y = vy0*t - 1/2*g*t^2 x = vx0*t where y is vertical distance measured from the height of the football player's hand, x is the horizontal distance, t is time, vy0 is the initial speed in the y direction, vx0 is the initial speed in the x ...
*October 5, 2012*

**physics**

The work is the force time the distance over which the force is exerted = 44.1kN * 38.3 mm =44,100 N * 0.0383 m
*October 5, 2012*

**physics**

First, find the acceleration: 7.3 = 14.4 - a*t Substitute 3 seconds into the above equation to find the acceleration a. This acceleration is due to the force of friction = ckf*m*g where ckf is the coefficient of kinetic friction, m is the mass of the puck, and g is the ...
*October 5, 2012*

**Math(Please help, thank you)**

yes
*October 5, 2012*

**physics**

Matt runs along two sides of a right angle triangle. If Ashley runs along the third side, this is the miniumum distance between Matt's initial and final points. Her distance is, using the Pythagorean theorem, (30^2 + 40^2)^0.5
*October 4, 2012*

**math**

Using the associative property of multiplication 5x(20x63) = (5x20)x63 5*20 is 100, and then its easy to multiply another number by 100
*October 4, 2012*

**physics**

Geosynchronous means that the satellite orbits the earth at the same rate that the earth rotates about its axis, or 1 rev/24 hours. Use this information to plug into the formula for the speed as a function of period of rotation
*October 4, 2012*

**physics**

From Boston to San Francisco, the speed of the plane relative to the ground is (240 - 41) = 199 m/s From San Francisco back to Boston, the speed is (240 + 41) = 281 m/s c) The average speed is just (199 + 281)/2
*October 4, 2012*

**physics**

For every 5.7 m that the swimmer travels in a line perpendicular to the river bank, the current pushes him 2.2 m parallel to the river bank, so that the swimmer actually has to travel farther than 10 m to cross. The parallel displacement can be found by setting up similar ...
*October 4, 2012*

**physics**

The force of the centripetal acceleration must be greater than or equal to the force of gravity, or m * v^2 / r >= mg v^2 / 20 >= 9.8 solve for v
*October 4, 2012*

**physics**

The circle is horizontal, so there is no force from gravity along the string. 45N >= m*v^2 /r 45N >= 0.33*v^2/0.65
*October 4, 2012*

**Algebra**

You'll have to calculate it taking into account the different ways you could wrap the box. If you wrap it around the perimeter perpendicular to the 7inch length, and then closing on the two 4.5x4 faces,you need wrapping paper with a length of 4.5*2+4*2 = 9+8 = 17 and width...
*October 4, 2012*

**check my precalc**

2. yes, 4 (the highest degree is of the term 4x^4) 4. good! as long as 1/2x means 0.5* x and not 1 / (2*x) 6. Expanding x(x-1) = x^2 - x; the degree is 2 (from the term x^2) 8. good 10. good 12. good
*October 4, 2012*

**check my precalc**

2. yes, 4 (the highest degree is of the term 4x^4) 4. good! as long as 1/2x means 0.5* x and not 1 / (2*x) 6. Expanding x(x-1) = x^2 - x; the degree is 2 (from the term x^2) 8. good 10. good
*October 4, 2012*

**algebra**

The distance traveled by the 9:00 train from 10:00 onward is x(9:00) = 36 + 36 * t Where t is the time in hours after 10:00 The distance traveled by the 10:00 train from 10:00 onward is x(10:00) = 42 * t Set these two equal to each other to find the time at which they have ...
*October 4, 2012*

**physics**

43 - ckf * 140 = m*a where ckf is coefficient of kinetic friction. In your textbook ckf is probably represented as the greek letter mu, but it's really hard to write greek letters here. . . m is the mass of the sled, and a is its acceleration. Since the sled is moving at a...
*October 4, 2012*

**physics**

35 - ckf * 16 = m*a where ckf is coefficient of kinetic friction. In your textbook ckf is probably represented as the greek letter mu, but it's really hard to write greek letters here. . . m is the mass of the sled, and a is its acceleration. x = 1/2 * a * t^2 v = a * t ...
*October 4, 2012*

**chemistry**

1). half life = ln(2) / lambda where lambda is the radioactive decay constant 2). A(t) = 12mCi * e ^ - (lambda * t) where t is time, A(t) is activity as a function of time 15 hr = ln2 / lambda solve for lambda convert 2.5 days to hours Then t = 2.5 days * (24 hrs / day) Plug ...
*October 4, 2012*

**Physics**

a) x = 1/2 * a * t^2 where x is distance, a is acceleration, and t is time 16 = 1/2 * a * 0.1^2 Solve for a (it's units will be cm/s) b) Now that you know the acceleration calculate x when t = 0.1 seconds (0.1 = 0.05 + 0.05), and then calculate x when t = 0.05 seconds. ...
*October 4, 2012*

**Physics**

v = a * t, where v is speed, a is acceleration, and t is time 110 m/s = a * 11 Solve for a
*October 4, 2012*

**Math**

1/2% of 50 = (1/2) * 0.01 * 50 Whenever you see a percent sign, you must divide by 100 (equivalently multiply by 0.01) to convert the percent to a decimal number
*October 4, 2012*

**Physics**

1.00 * 103 rpm is a unit of angular velocity. a = w^2 * r, where a is radial acceleration, and w is angular velocity, and r is the radius You need to express your answer as a multiple of g, which is in units of m/s^2 Convert w = 1.00 * 103 rpm to rps (rotations per minute to ...
*October 3, 2012*

**physics**

The period is given by T = 2 * pi * (r^3/(G*M))^0.5 where T is the period, r is the radius, G is the gravitational constant, M is the mass of the earth convert 621 km to meters look up the Gravitational constant and the mass of the earth in kg plug in the numbers, and solve
*October 3, 2012*

**algebra**

15 pounds per square inch * 30 square inches =
*October 3, 2012*

**math**

For every 1/2 inch of the scale, the actual width is 3 feet. 2 / (1/2) inches = 4 4 * 3 =
*October 3, 2012*

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