Thursday

November 27, 2014

November 27, 2014

Total # Posts: 973

**Chemistry**

1) A 0.1375-g sample of solid magnesium is burned in a constant-volume bomb calorimeter that has a heat capacity of 3024 J/C. The temperature increases by 1.126 degrees C. Calculate the heat given off by the burning Mg, in kJ/g and kJ/mol. 2) Determine the amount of heat in kJ...
*November 18, 2014*

**Chemistry**

1) Determine the amount of heat in kJ given off when 1.26 x 10^4 g of NO2 are produced according to the equation: 2NO (g) + O2 (g) --> 2NO2 (g) and delta (H) = 483.6 kJ/mol 2) A sheet of gold weighing 10 g and at a temperature of 18 degrees C is placed on a flat sheet of ...
*November 18, 2014*

**physics**

What is the kinetic energy in MeV of a π–meson that lives 1.80×10-16 s as measured in the laboratory, and 0.840×10-16 s when at rest relative to an observer, given that its rest energy is 135 MeV?
*November 16, 2014*

**Maths**

4. Tonya is 1.3 meters tall. She stands 7 meters in front of a tree and casts a shadow 1.8 meters long. How tall is the tree?
*November 12, 2014*

**math**

a box of chalk and 2 staplers costs $10. 3 boxes of chalk and 2 staplers costs $18. find total cost of 1 box of chalk and 1 stapler
*October 30, 2014*

**precalculus**

one section of a suspension bridge has its weight uniformly distributed between twin towers that are 400 feet apart and rise 90 feet above the horizontal roadway. a cable strung between the tops of the towers has the shape of a parabola, and its center point is 10 feet above ...
*October 25, 2014*

**Physics**

as you are riding in a 1650-kg car, you approach a hairpin curve in the road whose radius is 50m. the roadbed is banked inward at anangle of 10 degrees. suppose that the road is dry and that the static friction coefficient between the tires and the asphalt road is .6 what is ...
*October 24, 2014*

**inequalities**

5(2x-4)+ 11< 10 -2(6-x)
*October 21, 2014*

**Math**

If z^2 = x^2 + y^2 with z>0, dx/dt=3, and dy/dt=6, find dz/dt when x=4 and y=3. Answer: \displaystyle \frac{dz}{dt} =
*October 20, 2014*

**Calculus**

At noon, ship A is 40 nautical miles due west of ship B. Ship A is sailing west at 19 knots and ship B is sailing north at 16 knots. How fast (in knots) is the distance between the ships changing at 7 PM?
*October 20, 2014*

**Chem---DrBob222**

What is the formula for 2-bromomethylpropane ?
*October 14, 2014*

**Physics**

A highway curve with a radius of 750 m is banked properly for a car traveling 100 km/h. If a 1600- kg Porshe 928S rounds the curve at 220 km/h, how much sideways force must the tires exert against the road if the car does not skid?
*October 10, 2014*

**Physics**

Use kinematic equations,velocity at max height is zero, so 0=9.75^2-19.6(X-399)=403.9m. Then for speed at ground just do V^2=-19.6(0-403)=88.9 m/s
*October 10, 2014*

**Physics Help Please!!!!**

1) A high-speed maglev train is traveling with a changing velocity. what can be said about the forces acting on the train? 2) An automated vehicle in a warehouse is traveling at a constant velocity. what can be said about the forces acting on the vehicle?
*October 1, 2014*

**math**

out of 32 students in a class, 5 said they rode their bikes to school. Based on these results, how many of the 800 students ride their bikes to school?
*September 28, 2014*

**English**

Thank you SO MUCH.
*September 24, 2014*

**English**

Which would be grammatically correct: We both had a goal and objective in mind to get our jobs done. or We both had a goal and objective in mind to get the job done. Thanks!
*September 24, 2014*

**Algebra Based - Physics Help Please!!!!**

a) In 1897, Madeline Boardman won the long-drive contest during the U.S. Women's Amateur Golf Tournament. Her winning drive was 125 m. if the ball was hit off the tee at a 45 degree angle, what did the magnitude of its initial velocity have to be for her to make the ...
*September 24, 2014*

**Physics - Force**

A high-speed maglev train is traveling with a changing velocity. what can be said about the forces acting on the train? Thanks!
*September 24, 2014*

**physics**

If a pull of 350 N accelerates a 38-kg child on ice skates at a rate of 7.3 \frac{m}{s^2}, what is the frictional force acting on the skate?
*September 15, 2014*

**Physics Help Please**

a) On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? b) On the same conveyor belt as described in problem a), the part ...
*September 11, 2014*

**Physics Help**

a) On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? On the same conveyor belt as described in problem a), the part ...
*September 11, 2014*

**Physics Help**

On the Acme W&W company production line, parts have to be transported 100 m by conveyor belt to a machine area. The parts move at a constant speed of 2.5 m/s. How much time does it take to move a part 100 m? Show steps please! Thank you!
*September 11, 2014*

**6th Grade Math**

Thank you to all that helped
*September 2, 2014*

**6th Grade Math**

Can someone please show me how to work this problem below? Jacob earned $80 babysitting and deposited the money into his savings account. The next week he sepnt $85 on video games. Use the integers to describe the weekly changes in Jacob's saving account balance.
*September 2, 2014*

**Statics**

If both the projection Pa and component Fb of the force F are 305 N, determine the magnitude F and the orientation è of the b-axis. The angle between the negative y axis and the a- axis is 70 degrees. The angle between the negative y axis and the force F is 108 degrees...
*September 1, 2014*

**Statics**

The figure shown includes an x, y, and z axis. On the positive x-y plane, force F2 points toward the origin with a magnitude of 3kN and an angle theta between it and the positive x axis. On the negative x-y plane, force F1 points toward the origin with an angle of 27 degrees ...
*September 1, 2014*

**Statics**

The two forces shown act in the x-y plane of the T-beam cross section. If it is known that the resultant R of the two forces has a magnitude of 3.8 kN and a line of action that lies 14° above the negative x-axis, determine the magnitude of F1 and the orientation è ...
*September 1, 2014*

**Statics**

If both the projection Pa and component Fb of the force F are 305 N, determine the magnitude F and the orientation è of the b-axis. There is a 70 degree angle from the negative y-axis to the a-axis. There is a 108 degree angle from the negative y-axis to the force.
*September 1, 2014*

**Physics**

Determine the magnitude of the vector sum V=V1+V2 and the angle theta(x) which V makes counterclockwise from the positive x-axis. V1 = 34 units and makes a 20 degree angle with the +x axis V2 = 28 units and forms a 3,4,5 triangle with the -x axis
*August 27, 2014*

**Physics**

Determine the magnitude of the vector sum V=V1+V2 and the angle theta(x) which V makes counterclockwise from the positive x-axis. V1 = 34 units and makes a 20 degree angle with the +x axis V2 = 28 units and forms a 3,4,5 triangle with the -x axis
*August 26, 2014*

**biology**

Also the transmembrane protein functions as an ion and solute channel.
*August 21, 2014*

**biology**

You want to design an experiment to test if a bacteria affects a transmembrane protein. What types of controls should you use to eliminate effects of confounding variables?
*August 21, 2014*

**ALGEBRA**

A JAR CONTAINING 3 RED 4 BLUE AND 5 WHITE MARBLES WHATS THE CHANCE OF DRAWING FIRST A RED AND THEN WITHOUT REPLACEMENT A WHITE MARBLE?
*August 21, 2014*

**math**

thank you
*August 11, 2014*

**math**

How to write it in expanded form 12.0067 Is this answer right 1*10+2*1+6*1/1000+7*1/10000
*August 11, 2014*

**math**

How to write it in expanded form 12.0067 Is this answer right 1*10+2*1+6*1/1000+7*1/10000
*August 11, 2014*

**math**

How to write it in expanded form 12.0067
*August 11, 2014*

**Math**

Find an equation of the curve that satisfies the given conditions: (d^2y/dx^2)=6x, the line y=5-3x is tangent to the curve at x=1
*July 29, 2014*

**Math**

Suppose you own a tour bus and you book groups of 20 to 70 people for a day tour. the cost per person is $30 minus $0.25 for every ticket sold. Gas and other miscellaneous costs are $200. Part a) Write the revenue and cost functions for this situation Part b)Write the profit ...
*July 29, 2014*

**Calculus **

A container in the form of a right circular cone (vertex down) has a radius of 4m and height of 16m. If water is poured into the container at the constant rate of 16m^3/min, how fast is the water level rising when the water is 8m deep. V=(pi/3)(r^2)h
*July 27, 2014*

**calculus**

ddx(sin(x3)+(sin(x))3) =ddx(sin(x3))+ddx((sin(x))3) =3⋅(sin(x))2⋅ddx(sin(x))+cos(x3)⋅ddx(x3) =3x2⋅cos(x3)+3⋅cos(x)⋅(sin(x))2
*July 17, 2014*

**Math**

A container in the form of a right circular cone (vertex down) has a radius of 4m and height of 16m. If water is poured into the container at the constant rate of 16m^3/min, how fast is the water level rising when the water is 8m deep? V=(pi/)(r^2)h
*July 17, 2014*

**Chemistry **

For each of the following examples, decide whether it would be better to use the term molecule or formula unit. a. K2SO3 b. H2SO3 c. CCl4 d. NH4Cl
*June 5, 2014*

**Chemistry **

Complete and balance the reactions A) (CH3)2NH(aq)+CH3COOH(aq)→ B) CH3CH2NH2(aq)+HBr(aq)→ C) CH3NH2(aq)+HCOOH(aq)→
*June 3, 2014*

**Physics**

A 275-gram ball bounces off a wall. The ball stays in a horizontal plane throughout the motion. The ball strikes the wall with a speed of 4.50 m/s at an angle of 𝜃 = 35.0o relative to the wall and rebounds with the same speed at the same angle. If the ball is in ...
*May 27, 2014*

**geometry**

there exists a circle with chords. the chords are congruent. their corresponding arc measurements are 80 degrees and 2x+10 solve for x
*May 21, 2014*

**algebra**

5(2x-4)+ 11< 10 -2(6-x)
*May 20, 2014*

**Chemistry **

Free-energy change, ΔG∘, is related to cell potential, E∘, by the equation ΔG∘=−nFE∘ where n is the number of moles of electrons transferred and F=96,500C/(mol e−) is the Faraday constant. When E∘ is measured in volts, Δ...
*May 18, 2014*

**Chemistry **

Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days. Assuming that none of the I−131 is eliminated from the person's body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours? Express...
*May 14, 2014*

**Chemistry **

Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days. Assuming that none of the I−131 is eliminated from the person's body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours? Express...
*May 14, 2014*

**Physics**

A daredevil performs a stunt in which he jumps with his motorcycle from a horizontal cliff 10m high. What must the initial velocity of the motorcycle be, in order for the stuntman to barely clear a 10m wide water canal at the base of the cliff?
*May 8, 2014*

**Physics**

A little girl is standing on a cliff and throws a ball straight down at a speed of 5m/s towards the ground below. How far has it fallen 2.0 seconds after it leaves her hand?
*May 8, 2014*

**Physics**

A ball leaves a table with an initial horizontal velocity of 2.4m/s. The height of the table is adjustable. In two runs, the height of the table is set at 2.5m and 5.0m respectively. Assume air resistance is negligible. What is the horizontal distance between the two landing ...
*May 8, 2014*

**calculus help**

Find the derivative of the function. y = integral from cosx to sinx (ln(8+3v)) dv lower limit = cosx upper limit = sinx y'(x) = ????
*May 7, 2014*

**Physics/Calculus**

It takes a force of 21,714lb to compress a coil spring assembly on a New York City Transit Authority subway car from its height of 8in to its fully compressed height of 5in. A. What is the assemblys force constant? B. How much work does it take to compress the assembly the ...
*May 2, 2014*

**Calculus/Physics**

A spring has a natural length of 10in. An 800lb force stretches the spring to 14in. A. Find the force constant B. How much work is done in stretching the spring from 10 to 12 inches? C. How far beyond its natural length will a 1600lb force stretch the spring.
*May 2, 2014*

**Calculus/Physics **

It took 1800J of work to stretch a spring from its natural length of 2m to a length of 5m. Find the spring's force constant.
*May 2, 2014*

**Physics MCQ - Quick check**

Thanks Damon
*April 28, 2014*

**Calculus**

The following are about an infinite region in the 1st quadrant between y=e^-x and the x-axis. B)Find the volume of the solid generated by revolving the region about the y-axis Part A was solved below. Does anyone know how to do Part B?
*April 27, 2014*

**Calculus**

Thank you. What about part B?
*April 27, 2014*

**Calculus**

The following are about an infinite region in the 1st quadrant between y=e^-x and the x-axis. A) Find the area of the region B)Find the volume of the solid generated by revolving the region about the y-axis
*April 27, 2014*

**Calculus**

Limit as x approaches 0 of x(1-cosx)/t-sinx. Confused on how to get this answer.
*April 21, 2014*

**Calculus **

Determine the behavior of limits A. Limit as x approaches 1 of: (log x)/((x-1)^2) B. Limit as x approaches infinity of: ((x-1)^2)/(log x))
*April 21, 2014*

**Calculus**

Thanks
*April 21, 2014*

**Calculus **

Evaluate limit as x approaches 0 of: csc^2(7x)tan(2x^2)
*April 21, 2014*

**CHEMISTRY HELP !!!! **

As a standard voltaic cell runs, it "discharges" and the cell potential decreases with time. Explain.
*April 19, 2014*

**Calculus Help!!!!!**

sketch the graph of the following. Show all your work and include all the important points and asymptotes. also find y' and y'' ? y= (x^3)/(x+1)^2
*April 16, 2014*

**Physics**

A "reference ring" with moment of inertia Ic rests on a solid disk torsion pendulum with a moment of inertia I0. a) What is the period T0 for the motion with the disk alone? b) What is the period T1 for motion with the combined system? c) Use the expressions from a) ...
*April 14, 2014*

**algebra**

solve the following: 300e^.06x = 1500
*April 11, 2014*

**algebra**

Evaluate: log base 5 379
*April 11, 2014*

**CHEMISTRY HELP !!!! Check**

using Kb, for NH3 (from Appendix E), calculate Ka for the NH4+ ion. Kb for NH3 is 1.81 x 10^-5 Ka for NH4+ is Kw / Kb = 10^-14 / 1.81 x 10^-5 = 5.52 x 10^-10
*April 10, 2014*

**Calculus Help Please!!! Urgent!!!**

If x^3 - y^3 =3 , use only implicit diff. to find d^2y/dx^2 . Express your answer in terms of x and y only and write is as a proper fraction that is completely simplified as much as possible. d^2y/dx^2= -6x/y^5 (this is the answer I should get but i dont know how to show steps...
*April 9, 2014*

**Calculus Help Please!!!**

A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 40 cm/s. Find the rate at which the area within the circle is increasing after each of the following. after 1 s = after 3 s = after 7 s =
*April 2, 2014*

**Calculus Help Please!!!**

Consider the following. f(x) = 8x (square root of (x − x^2)) (a) Use a graph to find the absolute maximum and minimum values of the function to two decimal places.
*April 1, 2014*

**Damon**

The question was like this!
*March 30, 2014*

**Calculus Help Please!!!**

Verify the given linear approximation at a = 0. Then determine the values of x for which the linear approximation is accurate to within 0.1. (Enter your answer using interval notation. Round your answers to three decimal places.) ln(1 + x) ≈ x xE
*March 30, 2014*

**Physics**

Two pucks with similar masses collide with each other over a nearly frictionless surface. At the moment of collision, a sharp knocking sound is produced. Is this collision elastic or inelastic? Explain.
*March 30, 2014*

**Physics**

Consider an isolated system consisting of two masses, each of which has a velocity vector in two dimensions. When these two masses collide the total momentum of the system is conserved. (a) Show that if the total momentum of the system is conserved then the component momenta ...
*March 30, 2014*

**algebra**

The monthly cost of driving a car depends on the number of miles driven. Lynn found that in May her driving cost was $310 for 140 mi and in June her cost was $450 for 700 mi. Assume that there is a linear relationship between the monthly cost C of driving a car and the ...
*March 29, 2014*

**Physics**

A 4700 kg vehicle on a level surface experiences a force applied due to the engine of 3700 N forward. If the force of friction acting on the vehicle is 189 N backward: Determine the values of the other forces acting on the vehicle. Draw a free body diagram and determine the ...
*March 20, 2014*

**CALCULUS HELP**

Let r(x)= f(g(h(x))), where h(1)=4, g(4)=5, h'(1)=3 , g'(4)=5 and f'(5)=7. find r'(1).
*March 20, 2014*

**Calculus Help**

Use logarithmic differentiation to find the derivative of the function. show steps please! y=(e^-xcos^2(x))/(x^2+x+1)
*March 16, 2014*

**Calc**

I was trying to solve the same question and couldnt find the domain. if someone can help me with it, I will be thankful.
*March 16, 2014*

**Calc**

what is the domain?
*March 16, 2014*

**Calculus**

Find equations of both the tangent lines to the ellipse x^2 + 4y^2 = 36 that pass through the point (12, 3). smaller slope y= larger slope y=
*March 14, 2014*

**Physics**

Assume a spring has an un-stretched length Xo. Write an expression for the elastic potential energy of the spring in terms of the position of the end of the spring X and its spring constant K.
*March 14, 2014*

**Physics**

Assume a spring has an un-stretched length Xo. Write an expression for the elastic potential energy of the spring in terms of the position of the end of the spring x and its spring constant k.
*March 13, 2014*

**Physics**

Consider the gravitational potential, kinetic, and total mechanical energies of a cart moving down an inclined ramp. (Also, let gravitational potential energy be defined to be zero when the cart is at the bottom of the ramp. A. Write an expression for the gravitational ...
*March 13, 2014*

**Calculus **

Find all points on the graph of the function f(x) = 2 cos x + cos^2 x at which the tangent line is horizontal. (Use n as your arbitrary integer.) smaller y-value (x,y)= larger y-value (x,y)=
*March 9, 2014*

**Math**

What is an equation for the line that passes through points(4,-4) and (8-4)?
*March 9, 2014*

**Calculus Help**

Find a parabola with equation y = ax^2 + bx + c that has slope 6 at x = 1, slope −14 at x = −1, and passes through the point (2, 17).
*March 7, 2014*

**Algebra word problems **

You have a total of $175 in $5 and $20 bills. The number of $5 bills you have is 3 more than 4 times the number of $20 bills. How many of each type of bill do you have?
*March 6, 2014*

**math 2**

255
*March 6, 2014*

**Physics**

COULD I GET SOME HELP?
*March 3, 2014*

**Physics**

A dynamics cart with a friction pad is placed at the top of an inclined track and released from rest. The cart accelerates down the incline at a rate of .60m/s^2. If the track is angled at 10 degrees above the horizontal, determine the coefficient of kinetic friction between ...
*March 3, 2014*

**Physics**

A baseball player rounds third base and is heading for home when he is signaled by the base coach to slide. The player has a speed of 3.5m/s when he begins to slide and he travels through a linear distance of 1.50 meters before coming to rest. Determine the coefficient of ...
*March 3, 2014*

**Calculus Help**

Let P(t) be the percentage of Americans under the age of 18 at time t. The table gives values of this function in census years from 1950 to 2000. (I didnt put the table here because it will not display well so the table has basically t as time from 1950 to 2000 and P(t) values...
*March 2, 2014*

**Calc Help Please**

I did some of them so can you help me with the rest. Consider the piecewise functon f(x) = (4x^2-3)/(3x^2-15) x<(-2) square root of(4-x^2) (-2)<-x<-(2) 5 x>2 lim x->-2^- f(x)= ?????? lim x->-2^+ f(x)= 0 f(-2)= 0 f(4) = 5 list the values of x for which f(x) is...
*February 28, 2014*

**Math**

the smallest regulation golf ball has a volume of 2.48 cubic inches. if the diameter of the ball were increased by 10%, or a factor of 1.1, what will the volume of the golf ball be?
*February 27, 2014*

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