Friday
April 18, 2014

Posts by Jennifer


Total # Posts: 1,940

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 heli...

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 li...

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...

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

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

physics
The dimensions are irrelevant. F = m*g = 0.77 * 9.8

Math
(66 + 66 + 66 + x) / 4 = 70 Solve for x

Math
Each side will be multiplied by 1.25, so the total perimeter will be multiplied by 1.25 20*1.25 =

Math
(73.5 + 73.5 + x )/3 = 75 Solve for x

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

Math
Sven's equation tells him how many dollars he spent per yo-yo.

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...

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 = 6...

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

health
I would think D--None of the conditions listed would necessarily prevent anyone from doing at least certain types of resistance exercises.

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

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...

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 Tuesda...

physics
x = 1/2 * g * t^2 22.5 = 0.5 * 9.8 * t^2 Solve for the time

ALG 2!!!
Use your calculator 5^2 = 5*5 = 25 25 - 16 + 25 = 50 - 16 =

math 7
In the US, 2000 pounds are in one ton. One quarter ton is 0.25 * 2000

Business Math
13 1/2 % = 13.5% = 0.135 monthly commission = 0.135 * 4230

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

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

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)

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 ...

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 ...

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 lowe...

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)

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 ...

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)

grammar
Valdezes' This would refer to something that belongs to the Valdez family

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...

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

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

math
1 nickel = $0.05 $0.05 / $1.00 = 0.05 = 5%

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...

CHEMISTRY
NH4OH breaks down into NH3 and H2O

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...

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.

Chemistry
Which of the following is a negative ion? Na+1,Na,O-2,O? All of them?

Chemistry
Which of the following molecules has the highest boiling point? CH4,BH3,NH3, SH2?

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

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

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 direct...

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

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 acceler...

Math(Please help, thank you)
yes

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

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

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

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

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 tria...

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

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

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...

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

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

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 bot...

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...

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 wh...

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 ...

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. sub...

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

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

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 r...

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

algebra
15 pounds per square inch * 30 square inches =

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

math
4. The distance is ((y2-y1)^2 + x2-x1)^2)^.5 plugging the numbers in: ((-6-2)^2 + (4 +2)^2)^.5 = square root of (64 + 36) a. square root of 52 Just type in 52 ^ 0.5 into your calculator imagine your axes are centered on a clock. The first quadrant (quarter on a clock) is x pos...

Math - Need urgent help!
1200 = 0.0333 * assessed value assessed value = .4 * market value solve the 1st equation for the assessed value, then plug this number into the second equation and solve for the market value

math
.15 * x = 3.75 Solve for x

Math
GP + 0.04 * GP = 23200, where GP is gross pay 1.04 * GP = 23200 Solve for GP

science/math/physics
start the shopper at (0,0) After pushing the cart 41 m south, he's now at (0, -41) After turning west and pushing the cart 28 m, he's now at (-28, -41) Now he has to turn 90 degrees again. . . he will then be going either north or south. . . south will result in the la...

Algebra II Funtion
Substitute f(4) = -7 into the equation for f(x): f(x) = x - 11 * (-7) f(x) = x + 77 f(x) =9x3 - x2 + 2 ; f(2) For this one, f(2) means find the value of f(x) when x = 2, so just put 2 into the equation for f(x) and solve

arithmetic
385 is between 300 and 400. Which is it closer to? (400) 4012 is between 4000 and 4100 Which is it closer to? 856 is between 800 and 900 Is it closer to 800 or 900? If you were given a number like 850, which is exactly between 800 and 900, you would round up to 900. That's...

math
You can simplify this expression by adding like terms: 8-3 = 5 2y + 9y = 11y So the equation becomes: 5 + 11y

Chemistry
The molar mass of H2 is 2.02 grams 1.25/2.02 is the number of moles of H2 multiply the number of moles of H2 by Avogadro's number, and you have the number of molecules of H2 multiply the number of molecules of H2 by 2 and you have the number of atoms of H

Physics
First, make sure all units are compatible: Convert 15 minutes to hours, since the speeds are listed in km per hour. 15 minutes / 60 min/hr = .25 hours Set up algebra equations: Then let x be the distance traveled by the car that travels at 70 km/hr Let y be the distance travel...

thermodynamics
P1 * V1 = P2 * V2 Where P1 and V1 are the initial pressure and volume, P2 and V2 are the final pressure and volume. 1 atm * 100 ft^3 = P2 * 1 ft ^3 P2 = 100 atm; use your book or the internet to find a conversion factor from atm to psi

Math
First you need to know what you are rounding off to -- the nearest ten, the nearest cent, the nearest 100? . . . Here's an example: 1558.23 Round 1558.23 to the nearest tenth: 1158.23 is between 1158.2 and 1158.3; it's closer to 1158.2, so 1158.23 rounded to the neares...

Science
Overpopulation occurs when a population outstrips the available resources to provide a basic standard of living. Consumption overpopulation occurs when a population outstrips the available resources to provide a basic standard of living, plus an additional consumptive standard...

Math
There are 2 digits in the number of national parks, and this number is less than 30 Therefore, you know that the number of parks is between 10 and 30 Both digits are even. . .there are only a few numbers between 10 and 30 that have 2 even digits. They are 20, 22, 24, 26, 28 On...

Physics
Your question is missing some units 8.9 what? 8.9 miles per hour? 8.9 feet per second? To find the distance in inches that Larry runs you multiply average speed * time, but you first might have to do some conversions to make sure units are compatible. For example if Larry'...

physics
the net force acting on the boat is 2100 N - 1600 N = 500 N a) Force = mass * acceleration 500 N = 1200 * a Solve for a, the acceleration in m/s^2 b) distance = 1/2 * a * t^2 where t is time distance = 1/2 *a*40^2 Plug in the acceleration from (a) and solve for the distance in...

Algebra II
This will be factored into an expression of the form (A*a + B)(C*a + D) Multiplying out: A*C*a^2 + A*D*a + B*C*a + B*D = A*C*a^2 + (A*D + B*C)*a + B*D = 12a^2-17a-5 which means A*C = 12 A*D + B*C = -17 B*D =-5 Then start trying whole numbers. . .B and D have to be +/- 1 or +/-...

Math
1. Romeo, Juliet, _ _ _ _ 2. Juliet, Romeo, _ _ _ _ 3. _ Romeo, Juliet _ _ _ 4. _ Juliet, Romeo _ _ _ 5. _ _ Romeo, Juliet _ _ 6. _ _ Juliet, Romeo _ _ 7. _ _ _ Romeo, Juliet _ 8. _ _ _ Juliet, Romeo _ 9. _ _ _ _ Romeo, Juliet 10._ _ _ _ Juliet, Romeo There are 5*2 possibiliti...

Math
40^2 = 1600 50^2 = 2500 So his age has to be between 40 and 50 What number between 40 and 50 when squared is a number between 1800 and 1900? 43^2 = 1849 if he was 43 in the year 1849, then he was 0 (the age he was born) in ???

Math
Let c be the number of chocolate chip cookies, and b be the number of brownies. b + c = 11 0.4 * c + 0.5 *b = 5.10 Use algebra to solve for b and c

physics
E = k * q/r^2 The distances all have to be converted to meters because you want everything in SI units a) at x = 0, the field from the first charge is k * 8.71 / 0.03m^2 the field from the 2nd charge is k * -28.6 / 0.09m^2 So the total electric field is the sum of these number...

Algebra
0.18 * 240

math
24 + 23 + 22 + 21 + . . . + 2 + 1 = This is the sum of all the cards in the deck. This sum has to be evenly divided by the numbers of piles, so divide this number by 6, and that is your answer.

Math
The average after the next student took the test was (20*75 + x)/21 = 76 Solve for x

physics
The impulse delivered to the ball is the change in momentum The beginning momentum is the mass of the object multiplied by its initial speed (0.1 kg * 4.0 m/s) = .4 kg m/s The final momentum is the mass of the object multiplied by its final speed (0.1 kg * 3.8 m/s) = 0.38 kg m...

Algebra
To find the greatest common factor, first list the factors of both numbers, then find which one is the greatest shared factor. For example, to find the greatest common factor of 20 and 30: Factors of 20: 1, 2, 4, 5, 10, 20 Factors of 30: 1, 2, 3, 5, 6, 10, 15 The common factor...

physics
This is like a right angled triangle with hypotenuse 86.4 and one side adjacent to the right angle 62.5. Use the pythagorean theorem: x^2 + 62.5^2 = 86.4^2 Solve for x.

calculus
y'> 0 on the intervals This means, for what range of x values is y' = 3x^2 - 3 positive, or in other words, for what range of x values is the graph of y' above the x axis y' < 0 This means for what range of x values is y'= 3x^2 -3 negative, or in othe...

science
x = 1/2 a * t^2 v = a * t where x is distance, a is acceleration, t is time, and v is speed First you have to get the units to match. You probably want your answer of acceleration to be in ft/second^2, so convert 330 mph to ft/s 330 miles/hour = 330 miles / 3600 s = 0.0916 mil...

6th grade math
square

statistics
80%

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