Friday

December 9, 2016
Total # Posts: 706

**Physics**

A parachutist with mass 79.7 kg jumps from an airplane traveling at a speed vi= 112 km/hr at a height H = 2570 m. He lands with a speed of vf = 5.21 m/s. What is the change in mechanical energy (J) of the earth- parachutist system from just after the jump to just before ...

*June 18, 2011*

**Physics Conservation of energy**

A box is pushed across the floor against a constant frictional force. The box is pushed across the room to the east in 30 seconds and returned to its starting point (pushed to the west) in 60 seconds. Which of the following is true about the work done and the power expended in...

*June 13, 2011*

**Physics Conservation of Energy**

A car traveling at 20 miles/hour stops in a distance of 15 feet when its brakes are locked. Assuming that the frictional force doesn't depend on speed, that same car traveling at 60 miles/hour will stop in a distance closest to a. 15 feet b. 45 feet c. 90 feet d. 135 feet ...

*June 13, 2011*

**chemistry**

An aqueous solution is 22.0% by mass silver nitrate, AgNO3, and has a density of 1.22 g/mL. what is the molality of silver nitrate in the solution?

*June 12, 2011*

**Physics**

A 645-kg elevator starts from rest and reaches a cruising speed of 1.47 m/s after 3.13 seconds. It moved 2.75 m during that time. What average power (W) is delivered by the motor during the initial acceleration of the elevator during the first 3.13 seconds? The correct ...

*June 6, 2011*

**Physics Block and ramp**

Thank you so much!!!! I get it.

*June 6, 2011*

**Physics Block and ramp**

A crate of mass 0.812 kg is placed on a rough incline of an angle 35.3 degrees. Near the base of the incline is a spring of spring constant 1140 N/m. The mass is pressed against the spring a distance x and released. It moves up the slope 0.169 meters from the compressed ...

*June 6, 2011*

**Physics- bungee jump**

A tall bald student (height 2.1 meters and mass 91.0 kg) decides to bungee jump off a bridge 36.7 meters above the river. The bungee cord is 25.3 meters long as measured from the attachment at the bridge to the foot of the jumper. Treat the bungee as an ideal spring and the ...

*June 6, 2011*

**Physics**

A construction crew pulls up an 87.5 kg load using a rope thrown over a pulley and pulled by an electric motor. They lift the load 15.5 m and it arrives with a speed of 15.6 m.s having started from rest. Assume that acceleration was not constant. How much work was done by the ...

*June 3, 2011*

**Physics - pulley**

A construction crew pulls up an 87.5-kg load using a rope thrown over a pulley and pulled by an electric motor. They lift the load 15.5 m and it arrives with a speed of 15.6 m/s having started from rest. Assume that acceleration was not constant. I have done the problem but am...

*June 3, 2011*

**Physics - Spring gun**

A spring gun is made by compressing a spring in a tube and then latching the spring at the compressed position. A 4.87-g pellet is placed against the compressed and latched spring. The spring latches at a compression of 4.87 cm, and it takes a force of 9.13 N to compress the ...

*May 29, 2011*

**Physics**

A child rides on a Ferris Wheel at the State Fair. The seat always faces to the right. There are three forces that act on the child,the child’s weight, W, the normal force of the seat,N, and the force of friction between the child and the seat, f. At which listed location...

*May 26, 2011*

**Physics - Multiple choice**

Correction: I believe it to be (a) not (c)

*May 26, 2011*

**Physics - Multiple choice**

An object is moving in a circle at a constant speed. From this you can be certain that a) there are at least two forces acting on the object, which balance each other. b) there are at least two forces acting on the object, which do not balance each other c) there must be more ...

*May 26, 2011*

**Physics**

A pendulum of length L=26.0 cm and mass m= 168 g is released from rest when the cord makes an angle of 65.2 degrees with the vertical. A) how far (m) does the mass fall before reaching its lowest point? My work: .26m - .109 = .151 m B) how much work (J) is done by gravity as ...

*May 26, 2011*

**math**

list all the factors of 84

*May 23, 2011*

**math**

At approximately what rate would you have to invest a lump-sum amount today if you need the amount to triple in six years, assuming interest is compounded annually?

*May 4, 2011*

**math**

NVM's preferred stock currently has a market price equal to $80 per share. If the dividend paid on this stock is $6 per share, what is the required rate of return investors would get from NVM preferred stock?

*May 4, 2011*

**trig**

sin^-1(sin5pi/6)

*April 19, 2011*

**trigonometry**

simplify sin7x-sin3x as a product of trig functions.

*April 19, 2011*

**trig**

convert the point with polar coordinates (2,7pi/6) into rectangular coordinates.

*April 19, 2011*

**trig**

The parametric equations for a curve in the x-y plane are x=2+t^2 and y=4-3t. Determine the points where the curve intersects the x-axis.

*April 19, 2011*

**trig**

simplify the expression: sin(theta+pi/4) + sin(theta-pi/4)

*April 19, 2011*

**trigonometry**

convert the polar equation r^2=2cos^2theta + 3sin^2theta into a rectangular equation

*April 18, 2011*

**trig**

simplify the expression sin(theta+pi/4) + sin(theta-pi/4)

*April 18, 2011*

**physics**

While on the moon, the apollo astronauts enjoyed the effects on gravity so much smaller then that ont he earth. If neil armstrong jumped up on the moon with the initial speed

*April 18, 2011*

**algebra **

Suppose the speedometer in your car reads 55.0 mph also written as mile/hour. What is your speed in m/sec? (1 km = 0.621 mi.) unit factor methond soooo lost on this one please help!!!

*April 3, 2011*

**math**

a piece of ribbon is 4 1/2 feet long. a piece of blue ribbon is 1 yd long. How many feet longer is the piece of red ribbon than the piece of blue ribbon?

*March 24, 2011*

**math**

find the sum estimate to cheack if the answer is reasonable

*March 22, 2011*

**math**

x|y 6|2 12|4 24|8 33|11

*March 21, 2011*

**MATH**

X|Y 25|17 32|24 46|38 59|51 COULD YOU PLEASE EXPLAIN HOW TO GET THE ANSWER.

*March 21, 2011*

**math**

find a rule for each table, write an equation for each rule. x|y 0|16 20|36 36|52 42|58

*March 21, 2011*

**5th grade math**

please show how to get the answer... w>2 d+6<15 s-1>4

*March 16, 2011*

**5th grade math**

please show how to get the answer... w>2 d+6<15 s-1>4

*March 16, 2011*

**5th grade math**

please show how to get the answer... w>2 d+6<15 s-1>4

*March 16, 2011*

**math**

could you show me how to get the answer.. name three soultions to the inequality,

*March 16, 2011*

**math**

w > 2 d + 6 < 15 s - 1 > 4 please explain

*March 16, 2011*

**5th grade math**

name three solutions of inequality. then graph the inequality on a number line. k<8

*March 16, 2011*

**Alg 1**

Graph -4x+y>-6 5y<=-x-20 Then give 2 ordered pairs that solve it& 2 ordered pairs that don't solve it

*March 13, 2011*

**ALGEBRA**

A farmer has 165 feet of fencing material in which to enclose a rectangle area. He wants the length x to be greater than 50 feet and width y to be no more than 20 feet. write a system to represent this situation.

*March 13, 2011*

**Alg 1**

The popultion of Medford High is 800 students & the population of WEstville High is 1240 students. Medfords pop. has been increasing by 30 students per year, while westville has been decreasing by 25 students per year. In how many yearas will the populations be the same. how ...

*March 9, 2011*

**5th grade math**

3m=63

*March 8, 2011*

**math**

y-28=98

*March 3, 2011*

**math**

c-68=78

*March 3, 2011*

**math**

d-14=13

*March 3, 2011*

**5th grade math**

use inverse operations and a property of equaility to solve the equations. x+13=42 x-12=37

*March 2, 2011*

**5th grade math**

get each variable by itself on one side of the equation. x-45=90 n+23.4=36.9

*March 2, 2011*

**Chemistry**

Yea so it would be K2CrO4

*February 25, 2011*

**Math**

prime and composite arrays are hard .Help please .

*February 22, 2011*

**math**

why the formula for finding the surface area of a rectangular prism is helpful.

*February 6, 2011*

**Math**

Julia deposits $900 in a savings certificate that pays 6.5 % annually. How much money will Julia have at the end of one year?

*January 31, 2011*

**physics**

a woman is mowing her lawn. she is pushing on the handle with a force of 250 newtons. if the handle is at a 40 degree angle with the horizontal, resolve the vector. ??

*January 10, 2011*

**physics**

a man is pulling a 100kg crate with a force of 250 newtons. the rope makes a downward angle of 30.0 degrees with the horizontal. if the crate is sliding at a constant rate, calulate the coefficient. ?? how do i do this??

*January 10, 2011*

**physics**

a 35.5kg box slides down an incline plane with a 25 degree angle at a constant rate. how do i calculate the coefficient of friction

*January 10, 2011*

**Math**

what is the answer ?

*January 9, 2011*

**UNCP**

n(t)=-3t^+23t^2=8t Rewrite the formula by factoring the right-hand side completely. b) Use the factored version of the formula to find N(3) maximum number of components assembled

*January 7, 2011*

**UNCP**

In a study of worker efficiency at Wong Laboratories it was found that the number of components assembled per hour by the average worker t hours after starting work could be modeled by the formula. Rewrite the formula by factoring the right-hand side completely. b) Use the ...

*January 7, 2011*

**Statistics**

How large a sample from N(80,20) population is needed so that the sampling distribution of the mean has a standard deviation of 1?

*January 4, 2011*

**math**

An angry construction worker throws his wrench downward from a height of 128 feet with an initial velocity of 32 feet per second. The height of the wrench above the ground after t seconds is given by S(t)= -16t^2 - 32t + 128. a) What is the height of the wrench after 1 second...

*January 3, 2011*

**Physics**

A hill is 290 m long and makes an angle of 10 degrees with the horizontal. As a 68 kg jogger runs up the hill, how much work does gravity do on the jogger?

*December 16, 2010*

**organic chemistry**

What is the {\rm HCl} concentration if 54.2 mL of 0.100 M {\rm NaOH} is required to titrate a 30.0 mL sample of the acid?

*December 15, 2010*

**math**

write 1.06X as a sum

*December 6, 2010*

**physics **

The fastest recoded pitch in Major league baseball was thrown by nolan ryan in 1974. If this pitch were thrown horizontally, the ball would fall 0.809m(2.65 ft)by the time it reached home plate, 18.3m (60ft) away. how fast was ryans pitch?

*November 6, 2010*

**Earth Science**

If the date was March 22 and one saw the noon sun at 35 degrees south above the horizon, what latitude is one at?

*October 30, 2010*

**physics **

A package of medical supplies is released from a small airpllane flying a mercy mission over an isolated jungle settlement. The plane flies horizontally with a speed of 20 m/s and an altitude of 20 meters. How far from the release point will the package strike the ground?

*October 30, 2010*

**Earth Science**

Please determine the noon sun angle at the given latitudes on April 11: 40 degrees north 0 degrees

*October 29, 2010*

**Earth Science**

How many hours of daylight occur at the following locations on the specified dates? March 22 ---------------- 40 degrees north 0 degrees 90 degrees south December 22 ---------------- 40 degrees north 0 degrees 90 degrees south

*October 29, 2010*

**Physics **

A motor cyclist traveling at 30 m/s accelerates uniformly for 5 seconds to v= 40 m/s. H then maintains a constant velocity for the next 4 minutes. How far did the motor cyclist travel throughout the entire motion?

*October 28, 2010*

**algebra**

joshua had 5/6 of a tank of gas when he started his trip. if he used 1/10 of what was there what part of a tank was left at the end of the trip?

*October 22, 2010*

**physics**

Question part Points Submissions 1 0/1 5/15 Total 0/1 You ride your bike for 1.5 h at an average velocity of 11 km/h, then for 30 min at 15 km/h. What is your average velocity?

*October 18, 2010*

**Algebra**

7.14

*October 18, 2010*

**Physical Science**

A force of 400.0 N is exerted on a 1,250 N car while moving it a distance of 3.0m. How much work was done on the car?

*September 30, 2010*

**adult education**

You and a friend are invited to my garage sale.

*September 26, 2010*

**Physics**

An artillery shell is fired with an initial velocity of 300 m/s at 65.0° above the horizontal. To clear an avalanche, it explodes on a mountainside 37.5 s after firing. What are the x and y components of the shell where it explodes, relative to its firing point? x = ...

*September 26, 2010*

**math 7th**

64 over 96

*September 7, 2010*

**Statistics**

Calculate each binomial probability: a. X = 2, n = 8, ð = .10 b. X = 1, n = 10, ð = .40 c. X = 3, n = 12, ð = .70 d. X = 5, n = 9, ð = .90

*August 29, 2010*

**Statistics**

A lottery ticket has a grand prize of $28 million. The probability of winning the grand prize is .000000023. Based on the expected value of the lottery ticket, would you pay $1 for a ticket? Show your calculations and reasoning clearly.

*August 29, 2010*

**physics**

i don't know

*August 17, 2010*

**chemistry**

What volume of 4.50M HCl can be made by mixing 5.65M HCl with 250 mL of 3.55M HCl?

*July 24, 2010*

**math**

9m+n=24 m-8n=27 n= 24-9m 27= m - 8(24-9m) 27= m - 192 - 72m 219= -71m so m = 3.0845 Double check by entering this into the other equation. 9(-3.0845)+ (24-9(-3.0845) -27.7605 + 24 - -27.7605 = 24. so m = -3.0845 -3.0845 - 8(n)= 27 -8n= 30.0845 n= - 3.7606 m: -3.0845 n= -3.7606

*July 12, 2010*

**algerba**

-10xy - 15y / 5y I believe the expression simplifies to -2x - 3. The Y's cancel out when you divide by 5y.

*July 12, 2010*

**Chemistry**

If 10.0g of CaCl2 and 10.0g of NaCl are dissolved in 100.0mL of solution, what is the concentration of chloride ions? I found the molar mass of CaCl2 is 111.0g/mol; the molar mass of NaCl is 58.44g/mol. I divided 10g CaCl2/111.0g CaCl2 I divided 10g NaCl/588.44g NaCl and added...

*July 12, 2010*

**Chemistry**

So, 2C4H8O + 11O2 ---> 8CO2 + 8H2O Is that right?

*July 11, 2010*

**Chemistry**

It says to write the balanced equation for the complete combustion of cyclobutanol in Oxygen. I'm not even sure what the product is supposed to look like so how can I balance the equation? Please help. C4H8O + O2 ---> C4H8O

*July 11, 2010*

**chemistry**

You have to draw Lewis Dot structures and than use 1 of two approaches. The first is The vector addition approach, which is most helpful for smaller molecules. The 2nd approach is the center of charge approach, and you look to see where your negatives and positives are on your...

*July 11, 2010*

**Chemistry**

For which of the following reactions is the value of Delta H rxn equal to Delta H of formation? I. 2Ca(s) + O2(g) --> 2CaO(s) II. C2H2(g) + H2(g) --> C2H4(g) III. S(s) + O3(g) --> SO3(g) IV. 3Mg(s) + N2(g) --> Mg3N2(s). According to my answer key, the only one is ...

*July 11, 2010*

**Chemistry**

What is the de Broglie wavelength, in meters, associated with a proton. (mass = 1.673 x 10^-24g) accelerated to a velocity of 4.5 x 10^7 m/s? I tried dividing the mass by the velocity. I also multiplied the mass times the velocity, and neither answer came out correctly. The ...

*July 11, 2010*

**Chemistry**

Thank you very much.

*July 11, 2010*

**Chemistry**

One of the lines in the spectrum of a mercury vapor lamp has a wave length of 254nm. What is the energy, in kj/mol, of this electro magnetic radiation. The work I have done: (6.626 x 10^-34 x 3.0 x 10^8) all divided by (254 x 10^-9.) The answer I calculated is 7.82 x 10^-19. ...

*July 11, 2010*

**Chemistry**

If 10.0g of CaCl2 and 10.0g of NaCl are dissolved in 100.0mL of solution, what is the concentration of chloride ions? (the molar mass of CaCl2 is 111.0g/mol; the molar mass of NaCl is 58.44g/mol. I found individual molar mass of: Ca-40.08 Cl-35.45 Na-22.99 So I divided 10g ...

*July 11, 2010*

**Chemistry**

Thankyou both very much.

*July 10, 2010*

**Chemistry**

The density of Hg is 13.6g/cm^3. How many Hg atoms are present in 10.0cm^3 of Hg? I think the size of an atom is 6.22 x 10^23. The answer is 4.08 x 10^23. I need help getting to the answer.

*July 10, 2010*

**Finance**

Triple your investment in 12 months? Per quarter means you are receiving a 75 percent return on investment every quarter. 3/4 cause quarters implies 4 in the denominator.

*July 10, 2010*

**Chemistry**

Thankyou very much

*July 10, 2010*

**Chemistry**

I cannot figure this out. It seems so simple, and I should know it. The density of tungsten is 19.3g/cm^3 Express this value in lb/ft^3. I did 19.3g/cm^3 x 2.54cm/inch x 12 inches/1 foot = 588.264. Now 19.3g x 1 ounce/28g x 16 ounces/lb. = 11.03. After reading my answer key, ...

*July 10, 2010*

**Algebra 1**

I think you should just know ratios for this. If its 30-60-90 and b= 15, than A= 15/2=7.5 You get this because A is half the size of B. C is three times the size of C, so 7.5 x 3 = 22.5 So 7.5,15,22.5 Hope this helps.

*July 10, 2010*

**algebra**

Well if 0 units are produced, your profit is a loss of 262,500 which is primarily your fixed cost. Total revenue function is 98x. X is the number of units sold. I think marginal revenue is just revenues minus variable cost so 98x-23y would be marginal revenue. I might be wrong...

*July 10, 2010*

**MATH**

4-(-3)2 ÷ (-7x4+3) 4-(-6) / (-25) 10/-25 = -2/5 The reciprocal is -5/2 or -2.5. Hope this helps.

*July 10, 2010*

**Chemistry**

Thankyou very much for clearing that up.

*July 10, 2010*