Friday

July 29, 2016
Total # Posts: 138

**Calculus**

How do you differentiate sin^2(cos t) My work: =2sin(cos)(cost)(-sint)
*July 14, 2016*

**Geometry**

A construction crew wants to hoist a heavy beam so that it is standing up straight. They tie a rope to the beam, secure the base, and pull the rope through a pulley to raise one end of the beam from the ground. When the beam makes an angle of 40 degrees with the ground, the ...
*March 16, 2016*

**Physics of ice skating**

hello! so I know when learning to skate, you should position your skate at a 45 degree angle, but i'm not sure why. is it because if you just position them straight,the low friction of the ice won't allow you to move/ push forward? plus does the 45 angle allow you to ...
*January 2, 2016*

**Physics**

When the motor in the figure below raises the m = 1010kg mass, it produces a tension of 1.04E+4N in the cable on the right side of the pulley. The pulley has a moment of inertia of 78.9kgm^2 and a radius of 0.736m. The cable rides over the pulley without slipping. Determine ...
*October 16, 2015*

**algebra**

Vic buys a car with 10000 miles on it . He drives 100 miles a week. Eva buys a car with 7000 miles on it she drives an average of 400 miles a week. How many miles will the cars have on them when the number of weeks is the same. m= 100w + 10000 m= 400w + 7000
*May 18, 2015*

**Physics**

And how do you go about finding the other phase constant?
*April 28, 2015*

**Physics**

But how does that even make sense?????? The equation for a standing wave is y'(x,t) = 2Asin(kx)cos(omega * t)
*April 28, 2015*

**Physics**

The equation of a transverse wave traveling in a string is given by y(x,t) = 10 cos (π/2)(0.0050x - 8.0t + 0.57), in which x and y are expressed in centimeters and t in seconds. Write down the equation of a wave which, when added to the given one, would produce standing ...
*April 28, 2015*

**Chemistry**

A beam of light with a frequency of 7.61•1015 Hz hits the surface of the metal. What is the velocity of the electron ejected in m/s? (6 pts) How do you find the velocity based only off the frequency?
*April 15, 2015*

**Chemistry**

In an alternate universe, electron energies in an atom are found to obey the following equation where n is the principle quantum number: E = 3.0 x 10^(-19) J * nm * (1/n^2) ..where n is the principle quantum number A gas discharge lamp, like the lamps used in lab, contains ...
*April 15, 2015*

**Chemistry**

A photoelectric experiment is performed by separately shining a laser of 450 nm (blue light) and 560 nm (yellow light) on a metal surface and measuring the number and kinetic energy of the ejected electrons. The threshold frequency of the metal is 6.00•10^14 Hz. a. ...
*April 15, 2015*

**Chemistry**

A photoelectric experiment is performed by separately shining a laser of 450 nm (blue light) and 560 nm (yellow light) on a metal surface and measuring the number and kinetic energy of the ejected electrons. The threshold frequency of the metal is 6.00•10^14 Hz. a. ...
*April 15, 2015*

**Chemistry**

In an alternate universe, electron energies in an atom are found to obey the following equation where n is the principle quantum number: E = 3.0 x 10^(-19) J * nm * (1/n^2) ..where n is the principle quantum number A gas discharge lamp, like the lamps used in lab, contains ...
*April 15, 2015*

**Physics**

Suppose we had a straight tunnel, through Earth's center, to a point on the opposite side of the planet, and used it to deliver mail to the other side. With what speed would our packages pass through Earth's center. So: ag = (GM)/R2 Mins = (4/3)πR3*ρ So, I&#...
*April 4, 2015*

**Physics**

What is the ratio of the wight of a man when he is in a tunnel 1000 km below the surface of the Earth to his weight at the surface? ...I'm not sure how to proceed, not because I don't know how to do it, but because I have no idea how to come up with a(g) 1000 km inside...
*April 4, 2015*

**Physics**

If you take a pendulum clock from Paris to Cayenne, French Guiana, it loses 2.5 min each day. If the period of a pendulum of given length is proportional to 1/sqrt(g), and if g = 980.9 cm/s^2 in Paris, what is g in Cayenne? ...Um...I'm not entirely sure where to start. Do ...
*April 1, 2015*

**Physics**

A uniform cylindrical spool of mass M and radius R unwinds an essentially massless rope under the weight of a mass m. If R = 12 cm, M = 400 gm and m = 50 gm, find the speed of m after it has descended 50 cm starting from rest. Solve the problem twice: once using Newton's ...
*March 31, 2015*

**Physics**

So, "a uniform steel rod of length 1.20 meters and mass 6.40 kg has attached to each end a small ball of mass 1.06 kg. The rod is constrained to rotate in a horizontal plane about a vertical axis through its midpoint." There's more to the question, but the only ...
*March 30, 2015*

**Math**

What is the inverse of 987x=1 (mod 11)? What I've done so far is: GCD(987, 11) 987 = 89 * 11 + 8 GCD(11, 8) 11 = 1 * 8 + 3 GCD(8,3) 8 = 2 * 3 + 2 GCD(3,2) 3 = 1 * 2 + 1 ...So basically, the GCD(987, 11) is 1. So... 1 = 3 - 2 = 3 - (8 - 2 * 3) = 3 - 8 + 2 * 3 = 3 * 3 - 8 = ...
*March 24, 2015*

**Physics**

A dog, weighing 10.0 lbs, is standing on a flatboat so that he is 20 ft from the shore. He walks 8.0 ft on the boat toward shore and then halts. The boat weighs 40 lb, and one can assume there is no friction between it and the water. How far is he from the shore at the end of ...
*March 22, 2015*

**Physics**

So...the question is that a coil spring has a force constant of k = 4.0 lb/in. When the spring's axis is inclined at an angle 30 degrees form horizontal, a Weight = 2.0 oz ball is propelled to a height of 6.0 ft. By how much must the spring have been compressed initially...
*March 21, 2015*

**Physics**

A pendulum string has a length l = 4.0 ft. When the pendulum ball is released at 90 degrees to the vertical, it will swing down. A nail is located distance d below the point of suspension of the pendulum. Show that d must be at least 0.6l if the ball is to swing completely ...
*March 21, 2015*

**Science, Physics**

Concave mirrors can be used as for shaving or applying make up. The face must be inside the focus. You hold a concave mirror, with a focal length of 40 cm, about 30 cm from your face. Where is your image located? How much bigger than your face is the image?
*March 19, 2015*

**Chemistry**

But you don't know the temperature...
*March 18, 2015*

**Chemistry**

Provide the balanced reaction, the value of K, and E(cell) at equilibrium for the for the electrochemical cell created from the two half-cell reactions below Cr^(3+) + e ==> Cr^(2+) Fe^(2+) + 2e ==> Fe Well, I got the balanced reaction: 2Cr^(2+) + Fe^(2+) ==> Fe + 2Cr...
*March 18, 2015*

**Physics**

...I'm still confused. It's still not turning out right.
*March 12, 2015*

**Physics**

OH! I forgot to take the x component of Fg into account! Thanks!
*March 12, 2015*

**Physics**

A 2.0 lb block is given an initial speed of 4.0 ft/sec up an inclined plane starting from a point 2.0 feet from the bottom as measured along the plane. If the plane makes an angle (theta = 30 degrees) with the horizontal and the coefficient of friction is 0.20, how far up the ...
*March 12, 2015*

**Math**

When Mrs Lee was 44 years old, her son was twice her daughter's age. Mrs Lee would be twice her son's age when her daughter was 26 years old. How old would Mrs lee be when her daughter was 20 years old?
*January 30, 2015*

**math**

Summers garden is rectangle.4m long &2m wide she wants to put a fence around it.the fence post should be 2 m apart.How many fence post will Summer needs?
*January 22, 2015*

**Math**

Yancey collects plastic banks. He has three different banks: a pig, a cow, and a horse. How many ways can Yancey arrange his banks on a shelf
*January 10, 2015*

**Enlgish**

I just need an explanation from the instructions. I am a bit confused about it. EITHER use EACH of these nouns in a sentence which shows a human trait or characteristic OR choose one noun and use it in FIVE different sentences showing five human traits for the one noun. time a...
*November 8, 2014*

**Chemistry**

Sir, I don't want the answer, I'm having difficulty setting up the problem, once I can figure that out, I will try to solve. Thank you.
*November 7, 2014*

**Chemistry**

Calculate the mass (in grams) of sugar, C12H22O11, in 142.4 mL of a 1.39 M solution of sugar. (atomic weights: C = 12.01, H = 1.008, O = 16.00)
*November 7, 2014*

**Chemistry**

442 g * 0.0339 = 14.98 g
*November 7, 2014*

**English**

Read the following short paragraph. This paragraph is full of short, choppy sentences. Use your knowledge of sentence variety and prepositional phrases to improve the paragraph. Include all of the details in your revised version. The clouds seemed to loom over the baseball ...
*August 9, 2014*

**English**

Read the following short paragraph. This paragraph is full of short, choppy sentences. Use your knowledge of sentence variety and prepositional phrases to improve the paragraph. Include all of the details in your revised version. The clouds seemed to loom over the baseball ...
*August 8, 2014*

**math**

how to convert 5/8 to a decimal
*November 17, 2013*

**Math**

Is there anyway of checking to see if anyone else has posted a question that may help you without going through the entire list for your subject???????
*May 30, 2013*

**Math**

If you roll a die 48 times and 8 of the rolls result in a "5," what empirical probability was observed for the event "5"? (Give your answer correct to three decimal places.)
*May 30, 2013*

**Math PLEASE help**

Thanks but I do not need your help on this one anymore...
*May 30, 2013*

**Math/Statistics**

Three hundred twelve viewers were asked if they were satisfied with TV coverage of a recent disaster. Gender Female Male Satisfied 90 53 Not Satisfied 124 45 (a) Find P(satisfied). (Give your answer correct to two decimal places.) (b) Find P(satisfied | female). (Give your ...
*May 29, 2013*

**Math/Statistics**

A and B are events defined on a sample space, with the given probabilities. Find P(A and B). (Give your answer correct to two decimal places.) P(A | B) = 0.43 and P(B) = 0.75
*May 29, 2013*

**Math/Statistics**

Suppose that A and B are events defined on a common sample space and that the following probabilities are known. Find P(A or B). (Give your answer correct to two decimal places.) P(A) = 0.32, P(B) = 0.36, P(A | B) = 0.24
*May 29, 2013*

**Math/Statistics**

sorry this has not helped me at all....I am so confused on this stuff...
*May 29, 2013*

**Math/Statistics**

Consider the following. P(A) = 0.27 and P(B) = 0.36, A and B are mutually exclusive events (a) Find the probability P(A). (Give your answer correct to two decimal places.) (b) Find the probability P(B). (Give your answer correct to two decimal places.) (c) Find the probability...
*May 29, 2013*

**Math/Statistics**

Consider the following. P(A) = 0.31 and P(B) = 0.41, and P(A and B) = 0.1271 (a) What is P(A | B)? (Give your answer correct to two decimal places.) (b) What is P(B | A)? (Give your answer correct to two decimal places.) (c) Are A and B independent? yes no cannot be determined
*May 29, 2013*

**Math/Statistics**

Consider the following. P(A) = 0.31 and P(B) = 0.41, and P(A and B) = 0.1271 (a) What is P(A | B)? (Give your answer correct to two decimal places.) (b) What is P(B | A)? (Give your answer correct to two decimal places.) (c) Are A and B independent? yes no cannot be determined
*May 28, 2013*

**Math/Statistics**

Consider the following. P(A) = 0.27 and P(B) = 0.36, A and B are mutually exclusive events (a) Find the probability P(A). (Give your answer correct to two decimal places.) (b) Find the probability P(B). (Give your answer correct to two decimal places.) (c) Find the probability...
*May 28, 2013*

**Math/Statistics**

Suppose that A and B are events defined on a common sample space and that the following probabilities are known. Find P(A or B). (Give your answer correct to two decimal places.) P(A) = 0.32, P(B) = 0.36, P(A | B) = 0.24
*May 28, 2013*

**Math**

225
*January 31, 2013*

**3rd Grade Identify polygons**

Tim wants to make a polygon. He draws six straight line segments. Each line segment connects to two other line segments. Is Tim's shape a polygon? Explain.
*January 23, 2013*

**Math**

33/40
*November 29, 2012*

**c++**

The distance between two cities is 500 miles. Let us call these cities as CityA and CityB. Employees live in the CityA and travel to the CityB every day in the morning and come back in the evening on the same day except on Saturday and Sunday. They do not travel on vacations...
*October 17, 2012*

**Physics**

Assume a perfectly elastic collision between a 916g bat and a 145g baseball. Initially, the ball was moving at 32 m/s toward the ball and afterward it's heading away at 40 m/s. Find bat's speed before and after collision.
*October 10, 2012*

**Math**

30 way
*August 21, 2012*

**Math **

Logan wants to determine the distance across the river from points B to C. If she is able to determine the measures given on the map using surveyors’ tools, what is the distance between points B and C? Round the answer to the nearest tenth of a foot
*July 17, 2012*

**trig**

Find sin t ,cos t and tan t when the terminal side of an angle of t radians passes through (2 , 7)
*February 8, 2012*

**trig**

Find sin t ,cos t and tan t when the terminal side of an angle of t radians passes through (2 , 7)
*February 8, 2012*

**trig**

Thank you!
*February 8, 2012*

**trig**

Given theta is in the standard position and is in the first quadrant , if the terminal side of the angle theta is parallel to the line y=x+4 on ,find the measure of theta in degrees.
*February 8, 2012*

**Math **

The clothing stor had a sale for 75% off most of its shoes.Malik selected a pair of shoes that regulary sell for 80. What is the sale of Malik's new shoes.
*February 6, 2012*

**statistics**

using excel find the variance of a sample of 30 observations selected randomly. Given that the median is 14.7, the mode is 11 and the coefficientof variation is 45%.
*January 7, 2012*

**math**

One side of the rectangle lies along the line 4x+7y+5=0 , two of its vertices are (-3,1)and (1,1). find (i) the equations of the other three sides. (ii) the angle between the two diagonals of the rectangle . (iii) the area of the rectangle.
*December 27, 2011*

**math **

If the adjacent vertices of a square ABCD are A ( -2 , 0 ) , find - The equation of the two diagonals AC and BD - The point of intersection O of the two diagonals AC and BD - The equation of the altitude from O to the side CD - The centroid of the triangle OCD by finding any ...
*December 27, 2011*

**geomerty**

two sides of a triangle have lengths 45 inches and 50 inches. How long can the third side be?
*December 10, 2011*

**Science**

A car travelling at 27 m/s2 hits a wall with 48,600 N of force. What was the car's mass?
*November 4, 2011*

**Science**

A 0.2 kg falcon hits a mouse with a force of 5 N. What was its acceleration?
*November 4, 2011*

**Science**

The force of a 0.001 kg penny falling at 70 m/s2
*November 4, 2011*

**Science**

The force of a 4 kg bowling ball to accelerate to 6 m/s2
*November 4, 2011*

**Science**

Force of a 1500 kg rhino to accelerate to 4m/s2 How do I figure this out?
*November 4, 2011*

**math**

The number of cases for a disease has reduced by half every 10 years: 1970 - 21,168 1980 - 10,584 1990 - 5,292 Assume N is the number of reported cases t years after 1970. Which is a good model for N(t)? a) 21,168 (2)^t b) 21,168 (1/2)^t c) 21,168 (1/2)^t/10 d) 21,168 (2)^t/10
*October 31, 2011*

**programming**

develop a program that converts inches to centimeters(1 inch=2.54 cm). The program when runs should prompt the user to enter an inch value
*October 16, 2011*

**math**

Is 243 because 3rime 3 is nine and the nine times three is 27 so the answer is 243
*September 14, 2011*

**7th grade honors math**

Which equation represents an inverse variation? A.3x=2y B.2-2x+y=0 C.y squared= x D.xy=5 If you could tell me the anser then explain how you got it that would be awesome!
*March 14, 2011*

**math**

560 feet
*March 10, 2011*

**chemistry**

how do you calculate the % by mass of 3.55g of NaCl in 88g of water?
*February 10, 2011*

**AP US History**

Did Thomas Jefferson change his policy after becoming president and how? (i.e. he was for strict interpretation of the constitution and etc.) Thank you :)
*January 18, 2011*

**algebra**

the cost of living last year went up 3% fortunately alice swanson got a 3% rais in her salery from last year. This year she is earning $22,660 how much did she make last year
*November 22, 2010*

**algebra**

ya i see it sorry it should read don invested some money at 9%
*November 22, 2010*

**algebra**

don williams invested some money st 9% simple interest. At the end of the year, the total amount of his original principal and the interest was $6.540. How much did he originally invest
*November 22, 2010*

**chemsitry**

c. Use the enthalpy diagram provided above and apply Hess’s Law to determine the standard enthalpy of formation for C12O36H20N12 (s) using the results from part (a) and the following values: The standard enthalpy of formation of gaseous carbon dioxide is -393.5 kJ/mol The...
*October 23, 2010*

**chemsitry**

A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 °C. When the compound decomposes, the temperature of the water rises to 29....
*October 23, 2010*

**chemsitry**

b. The decomposition reaction may be written in this form: C12O36H20N12 (s) → 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O (l) In the enthalpy diagram below, the arrows represent standard enthalpy reactions. (3) denotes the standard enthalpy of decomposition of C12O36H20N12 (s...
*October 23, 2010*

**general chemistry**

A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 °C. When the compound decomposes, the temperature of the water rises to 29....
*October 23, 2010*

**essay**

can you help me to do my essay?
*October 8, 2010*

**Physics**

How many uranium atoms are there in 8.2 g of pure uranium? The mass of one uranium atom is 4 × 10^−26 kg.
*September 29, 2010*

**dress making**

I need help with Dress making (sewing machines) 04201501 and (introduction to sewing) 04201400. If anybody can help, thank you....
*June 1, 2010*

**Math 032 Algebra**

how to get the answer 16 1/9 2 3/15
*May 18, 2010*

**Physics Inertia : Merry-go-round**

if you want to find the final angular speed, wf, you take: momentinertiaMerryGoRound(initial angular speed) = (momentinertiaMerryGoRound + momentinertiaKid)(wf) then solve for wf
*April 19, 2010*

**English**

Can anyone tell me a quote about Myrtle in the Great Gatsby which proves: She is shown to be an attention seeker who tries to make an appearance of being in the upper class by criticizing the lower classes.
*March 22, 2010*

**Math**

Two cards are drawn at random from a standard deck of 52 cards. What is the probability that both cards are queens?
*March 10, 2010*

**Math**

Find the first three iterates of the function f(x)=x^2-2,if the initial value is -2.
*March 10, 2010*

**statistics**

3/10=.3 3/.2=15 prob=-6.8 2-68students
*March 8, 2010*

**statistics**

survey revealed two percent of students did not select stat. for biz. suppose we select a sample of 10 students. -what is the probability that 3 students selected stat. for biz? -how many students would you expect to select stat.for biz?
*March 8, 2010*

**vocabulary**

opining
*March 7, 2010*

**Math**

What is the cost of the room for that is used for 1.5 hours at the rate of $23 per month room and size of 288 sg ft?
*December 11, 2009*

**FINANCE 200**

A. PV = 9,000; rate = 9%; N = 2 years FV = PV x FVIF9%, 2 years = 9,000 x 1.188 = $10,692
*December 11, 2009*

**math**

2 forms of writing this number. 3,209,003,812?
*September 15, 2009*

**Clauses - Grammar**

Identify all the relative clauses in the following sentences. Which ones are restrictive and which are non-restrictive? How do you know? a. My sister Mary [who lives in Florida] is coming to visit us. = non-restrictive b. The girl [who had the most points] won the contest. = ...
*April 21, 2009*