Saturday

February 6, 2016
Total # Posts: 444

**Physics**

help pls
*February 4, 2016*

**Physics**

answers can be: 27.4, 13.2, 14.2, 11.42, 0.5 (all are N)
*February 4, 2016*

**Physics**

A 2kg mass, m1 and a 10 kg mass, m2 are in contact on a horizontal frictionless surface. a constant horizontal force 13.7 N in the positive X direction is applied to m1 and a constant horizontal force 10.7 N in the negative X direction is applied to m2. the masses stay in ...
*February 4, 2016*

**Physics**

a 61.6 kg person on a diet stand on a bathroom scale in an elevator. to their great pleasure the scale reads 46.8 kg. what is the acceleration of the elevator? (up is positive)
*February 4, 2016*

**Physics**

A 2 635-kg sailboat experiences an eastward force of 2 710 N by the ocean tide and a wind force against its sails with magnitude of 5 748 N directed toward the northwest (45° N of W). What is the direction of the resultant acceleration?
*February 4, 2016*

**Physics**

a stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12m/s. a stop watch measures the stone's trajectory time from top of cliff to bottom to be 8s. how far out from the cliff's edge does the stone travel...
*January 28, 2016*

**Physics**

an airplane has a velocity of 499 km/h relative to the moving air. at the same time, a wind blows northward with a speed of 87 km/h relative to the earth. the airplane is moving in an easterly direction relative to the earth. find speed of airplane to relative to earth.
*January 28, 2016*

**Physics**

A tennis player strikes a ball when it is 2.20m above the ground, with a velocity 18.7 m/s at 20 degrees above the horizontal. The net is 5m away horizontally and it is 0.90m high. after 0.37 seconds, what is the direction of the ball with respect to the horizontal?
*January 28, 2016*

**Physics**

the distance of a planet from its sun is 19000000 miles. if there are 29400000 seconds in one orbit, find the speed of the planet in its orbit about the sun. (assume a circular orbit)
*January 18, 2016*

**Biology**

Which of the following is true for the nucleus? A) It has no definite structure B) It is surrounded by membrane C) It is the eukaryotic cell's energy-producing organelle D) It is closely associated with the Golgi apparatus. E) It is always bluish purple in colour
*January 11, 2016*

**statistics help**

Nevermind, thanks for the help!
*December 8, 2015*

**statistics help**

What is SEm??
*December 8, 2015*

**statistics help**

Tests on a Chevy Cobalt incdicate a population mean of 32 mpg and a population standard deviation of 3.5 mpg. You take an SRS (sample random sample) of 10 cars to get a sample mean. What is the probability that your sample mean is greater than 34 mpg? I am not sure how to go ...
*December 8, 2015*

**Chemistry**

3. Choose the hybridization schemes for the following species. (a) AsBr6− sp sp2 sp3 sp3d sp3d2 (b) CSe2 sp sp2 sp3 sp3d sp3d2 (c) PbCl4 sp sp2 sp3 sp3d sp3d2 (d) SeO32− sp sp3 sp2 sp3d sp3d2 (e) BiF5 sp sp2 sp3 sp3d sp3d2
*December 7, 2015*

**Chemistry**

2. Which of the following molecules is/are trigonal pyramidal? N2O NH3 C2H2 SiF4 HN3 HCN SO3 H2S CF4 PF3 H2O BF3 COS O3 SO2 CS2 AsH3
*December 7, 2015*

**Chemistry**

1. [ PF4 ]+ (a) What is the electron-group geometry, according to VSEPR theory? (b) What is the molecular geometry? (c) Is this species polar or nonpolar?
*December 7, 2015*

**statistics help**

The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered investment properties. If a sample of 800 homes sold in 2004 is obtained what is the probability that AT LEAST 175 home are going to be used as investment property?
*December 6, 2015*

**statistics help??**

Someone flips a coin 50 times and gets 50 heads in a row. You suspect it is a 2 headed coin. Write the null and alternative hypotheses. Use the binomial theorem to get a p-value of getting exactly 50 hears in 50 trials.
*December 6, 2015*

**statistics**

A manufacturer claims that the mean lifetime of its lithium batteries is 1400 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 1380 hours with a standard deviation of 80 hours. Test the manufacturers claim. Use alpha = 0.05. Round the test ...
*December 5, 2015*

**stat**

Construct a 90% confidence interval for the population mean. Assume the population has a normal distribution. A same of 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation of 0.78. Round to the nearest hundredth. Answers: a) (2.41,3.42...
*December 5, 2015*

**statistics**

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Use a 95% ...
*December 5, 2015*

**physics**

A 189.4 kg uniform, horizontal beam is hinged at one end and at the other is supported by a cable that is at 37 degrees to the vertical. The beam is 3.85 m long. Calculate the magnitude of the force at the hinge.
*December 4, 2015*

**math**

verify sin0/sin0+cos0=tan0/1+tan0
*December 3, 2015*

**Chemistry**

For a Sc atom in ground electronic state: 1. how many electrons are there in 4s orbitals? 2. how many electrons are there in 3d orbitals? 3. how many electrons are there in 4p orbitals? 4. how many unpaired electrons are there? 5. to what block does Sc belong to in the ...
*November 27, 2015*

**Chemistry**

Consider the 5p orbital of a hydrogen atom. 1. how many different 5p orbitals are there? 2. how many radial nodes are there? 3. how many angular nodes are there? (i.e. how many nodal planes or surfaces, not including radial nodes)
*November 27, 2015*

**Chemistry**

For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...
*November 8, 2015*

**Science**

For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, explain how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room temperature...
*November 8, 2015*

**Chemistry**

For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...
*November 8, 2015*

**Chemistry**

For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...
*November 8, 2015*

**Chemistry**

This is just a question on my chem lab which is determining the molar mass of a volatile liquid. i dont understand how to answer this question, esp with the reasoning that has to be provided. help for this would greatly be appreciated!
*November 8, 2015*

**Chemistry**

For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...
*November 8, 2015*

**History **

What was Harriet Tubman rebelling against?
*November 3, 2015*

**Physics**

Consider a road over a hill where the top is shaped like a circular bump. This circular arc has its center in the hill below. As a 1200 kg car rounds the top of a hill at a speed of 20.0 m/s, it very breifly loses contact with the pavement. What is the radius of this circular ...
*October 24, 2015*

**english**

Which of the following options best demonstrates sentence fluency? a. The city looked beautiful in that it was lit by the sun while I was walking down the street. b. Walking down the street in the sunshine, the city looked beautiful. c. The city looked beautiful as I was ...
*September 24, 2015*

**Pre-Calculus**

how to make a xy table for the following greatest integer equation when using -1,-2,0,1,2 to plug into x f(x)=2[x], g(x)=[2x], f(x)=-[[x]], and g(x)=[[-x]]
*September 21, 2015*

**Physical Chemistry**

Calculate the difference between H and U when 1 mole of water is boiled at 373 K and 1 atm. The volume of 1 mole of perfect gas at 373 K is 0.03 m3 and the volume of liquid water may be neglected. (1 atm = 105 N m-2) what equations should be used ?
*September 2, 2015*

**science**

(Ans. (a) ∆U = ∆H = 0; q = 1.57KJ, w = −1.57KJ, (b) ∆U = ∆H = 0; q = 1.13KJ, w = −1.13KJ, (c) ∆U = ∆H = 0; q = 0, w = 0.)
*June 22, 2015*

**probability**

2. mean 50, variance 25
*April 11, 2015*

**PHYSICS**

In a power plant the high pressure turbine trips due to an unauthorised valve shutdown. What are a) what is the angular acceleration of the turbine blade? b) what is the distance travelled by a point on the rim of the turbine blade during the acceleration? c) what is the ...
*April 8, 2015*

**Math**

The inverse of a 2x2 matrix is given by: A=[a b A^1=1/ad-bc[d -b c d]. -c a]. If these two multiplied by each other gives the "identity matrix": [1 0 0 1]. then the inverse exists.
*April 8, 2015*

**math**

x=number of mystery books. 3x=total number of books on the shelf. x/5<10<x/4 is given. Get rid of the fifths and quarters by multiplying by 20. 4x<200<5x --> 40<x<50. The number of mystery books is anything between 40 and 50, multiply by 3 and you have ...
*April 8, 2015*

**PHYSICS**

A dock worker is loading a 25 kg solid cylindrical barrel to a ship by rolling it up a 9 meter long and 1.5 meter high ramp. At the top of the ramp the dock worker stop to go around the barrel but he loses the grip and the barrel starts to roll down the ramp without slipping ...
*April 8, 2015*

**Algebra**

x=4 gives inclination=k=1 in y=kx+m. It also states that m=4. y=x+4
*April 8, 2015*

**PHYSICS**

273.15°K is 0°C. Go from there to 232°C and its where tin melts. Conversion from °C to °K °K = °C + 273.15
*April 8, 2015*

**chemisty**

The initial concentration of NO2 in a closed container is 0.750M. At equilibrium the concentration of O2 is 0.125M. What are the concentrations of NO2 and NO at equilibrium? 2NO2 (aq) ==== 2NO (aq) + O2 (aq)
*March 1, 2015*

**chemistry**

The equilibrium concentration of NOCl = {0.0610}, NO = [0.0151, and Cl= [0.0142, what is the value of the equilibrium constant? Don't really get how to figure this out..anyone know? Thanks!!
*March 1, 2015*

**Physics**

you are wrong
*February 12, 2015*

**chemistry**

The density of acetonitrile, CH3CN, is 0.786 g/mL, and the density of methanol, CH3OH, is 0.791 g/mL. A solution is made by dissolving 15.0 g of methanol in 250.0 mL of acetonitrile. Assuming that the volumes of the solute and solvent are additive, what is the molarity of ...
*February 5, 2015*

**chemistry**

The Henry's law constant for CO2 is 3.1 x 10-2 mol/L-atm at 25°C. What pressure would be necessary in order to have a .25 M solution?
*February 5, 2015*

**chemistry**

The Henry’s Law constant for N2 in water at 30 oC is 6.0 x 10-4 M/atm, calculate the solubility of nitrogen gas in water at a partial pressure of 2.5 atm
*February 5, 2015*

**physics**

One particle has a mass of 2.86 x 10-3 kg and a charge of +7.32 μC. A second particle has a mass of 6.41 x 10-3 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.127 ...
*January 24, 2015*

**physics **

A particle of charge +18.1C and mass 7.06 × 10-5 kg is released from rest in a region where there is a constant electric field of +414 N/C. What is the displacement of the particle after a time of 3.06 × 10-2 s? Please explain the steps, thank you.
*January 19, 2015*

**physics **

Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 43 km away, 23° north of west, and the second team as 29 km away, 33° east of north. When the first team uses ...
*January 15, 2015*

**lauric acid **

what happens to the calculated molar has if the lauric acid is spilled before determining the freezing point?
*January 8, 2015*

**Algebra 2**

3.4e^2-2n - 9 = -4
*December 11, 2014*

**physics **

Due to a tune-up, the efficiency of an automobile engine increases by 4.00%. For an input heat of 1530 J, how much more work does the engine produce after the tune-up than before?
*December 4, 2014*

**physics **

The internal energy of a system changes because the system gains 180 J of heat and performs 338 J of work. In returning to its initial state, the system loses 111 J of heat. During this return process, what work is involved? If the work is done by the system, then give the ...
*December 3, 2014*

**physics Pls help **

A piece of glass has a temperature of 87.0 °C. Liquid that has a temperature of 32.0 °C is poured over the glass, completely covering it, and the temperature at equilibrium is 57.0 °C. The mass of the glass and the liquid is the same. Ignoring the container that ...
*November 22, 2014*

**Six grade percent**

plus 30 is more than half which is 25 so disregard the other way.
*November 16, 2014*

**Six grade percent**

7.5 is the answer it's 0.15*50 = 7.5
*November 16, 2014*

**math**

sorry! wrong calculation.
*November 16, 2014*

**math**

212 seata
*November 16, 2014*

**physics **

A 70.3-kg person puts on a life jacket, jumps into the water, and floats. The jacket has a volume of 3.07 x 10-2 m3 and is completely submerged under the water. The volume of the person's body that is underwater is 6.49 x 10-2 m3. What is the density of the life jacket?
*November 16, 2014*

**physics **

A copper (Young's modulus 1.1 x 1011 N/m2) cylinder and a brass (Young's modulus 9.0 x 1010 N/m2) cylinder are stacked end to end, as in the drawing. Each cylinder has a radius of 0.38 cm. A compressive force of F = 6100 N is applied to the right end of the brass ...
*November 12, 2014*

**physics**

got it, a) the stress is F/A= mg/A = 156(9.8)/7.44*10^-4= 2.05*10^6 N/m^2 B) F=S(delta y/ Lo)A,, solve for delta y delta y= (F/A)*(Lo/S) the value of F/A was found in part a, so substitute the answer in the second equation. 2.05*10^6(0.117/8.1*10^10)=2.96*10^-6m
*November 12, 2014*

**physics **

The drawing shows a 156-kg crate hanging from the end of a steel bar (S = 8.1 x 1010 N/m2). The length of the bar is 0.117 m, and its cross-sectional area is 7.44 x 10-4 m2. Neglect the weight of the bar itself and determine (a) the shear stress on the bar and (b) the vertical...
*November 12, 2014*

**Physics**

A dynamics cart with a mass of 1.70kg on a horizontal table is attached to a suspended mass of 0.40kg and released from rest. If a frictional of 2.0N opposes the motion of the cart how far does the cart travel in 1.5s
*November 9, 2014*

**Math**

Anna is correct I got a 5/5
*November 5, 2014*

**physics **

A cylindrically shaped space station is rotating about the axis of the cylinder to create artificial gravity. The radius of the cylinder is 159 m. The moment of inertia of the station without people is 4.23 x 109 kg·m2. Suppose 299 people, with an average mass of 67.0 ...
*November 2, 2014*

**Physics **

A bowling ball encounters a 0.760-m vertical rise on the way back to the ball rack, as the drawing illustrates. Ignore frictional losses and assume that the mass of the ball is distributed uniformly. The translational speed of the ball is 7.83 m/s at the bottom of the rise. ...
*November 2, 2014*

**physics **

A man holds a 185-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force , which is applied perpendicular to the forearm. The forearm weighs 24.3 N and has a center of gravity as indicated. ...
*October 28, 2014*

**Physics **

The wheels, axle, and handles of a wheelbarrow weigh W = 57 N. The load chamber and its contents weigh WL = 674 N. The drawing shows these two forces in two different wheelbarrow designs. To support the wheelbarrow in equilibrium, the man’s hands apply a force to the ...
*October 27, 2014*

**Physics**

A beam of particles is directed at a 0.017-kg tumor. There are 2.4 x 1010 particles per second reaching the tumor, and the energy of each particle is 5.2 MeV. The RBE for the radiation is 14. Find the biologically equivalent dose given to the tumor in 27 s.
*October 27, 2014*

**Physics , Pls help**

A space station consists of two donut-shaped living chambers, A and B, that have the radii shown in the figure. As the station rotates, an astronaut in chamber A is moved 2.06 x 102 m along a circular arc. How far along a circular arc is an astronaut in chamber B moved during ...
*October 25, 2014*

**physcs **

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 41.8 km/s and 64.6 km/s. The slower planet's orbital period is 8.84 years. (a) What is the mass of the star? (b) What ...
*October 21, 2014*

**guidance**

yes, it is B
*October 20, 2014*

**guidance**

it is aggression, you can't kick others, take it from that principle.
*October 20, 2014*

**Physics**

Got it: reasoning and solution.. the normal force exerted by the wall on each astronaut is the centripetal force needed to keep him in the circular path so, Fc=mv^2/r. rearranging and letting Fc=(1/3)mg yields r=3v^2/g= 3(29.1m/s)^2/(9.8m/s^2)=259m
*October 20, 2014*

**Physics **

Suppose the surface (radius = r) of a cylindrical space station is rotating at 29.1 m/s to provide artificial gravity. What must be the value of r for the astronauts to weigh 1/3 of their earth weight? Don't know how to start please help.
*October 20, 2014*

**physics**

I was able to solve this problem at firs, use the equation V=sqrt(R g tan theta) since you have two angles you will need to separate the equation into 2 Va= sqrt(r g tan a theta) Vb= sqrt (r g tan b theta) then solve for Vb Vb/Va= sqrt(r g tanb )/ sqrt(r g tan a theta) r and g...
*October 20, 2014*

**physics **

Curve A is banked at 11.2 °, and curve B is banked at an angle of 15.2 °. A car can travel around curve A without relying on friction at a speed of 14.5 m/s. At what speed can this car travel around curve B without relying on friction? Do I need to find radius in ...
*October 20, 2014*

**physics**

Thank you Don. A great way of clarifying through the steps, very detail oriented. Thanks again!
*October 20, 2014*

**physics **

Car A uses tires for which the coefficient of static friction is 0.333 on a particular unbanked curve. The maximum speed at which the car can negotiate this curve is 13.8 m/s. Car B uses tires for which the coefficient of static friction is 0.843 on the same curve. What is the...
*October 20, 2014*

**physics**

Thanks a lot Damon!
*October 12, 2014*

**physics **

A ball is dropped from rest at the top of a 5.89-m-tall building, falls straight downward, collides inelastically with the ground, and bounces back. The ball loses 5.34% of its kinetic energy every time it collides with the ground. How many bounces can the ball make and still ...
*October 12, 2014*

**CHEMISTRY**

As far as I know, Delta T means the difference in temperature. T final- T initial.
*October 12, 2014*

**physics**

ok I got the answer: a) Vf1=(m1-m2/m1+m2)*(Vi1) B) Vf2=[(2(m1)/m1+m2](Vi1)
*October 12, 2014*

**physics**

sorry I solved part C, I need help with a and b pls.
*October 12, 2014*

**physics**

A 2.20-kg ball, moving to the right at a velocity of +1.27 m/s on a frictionless table, collides head-on with a stationary 7.20-kg ball. Find the final velocities of (a) the 2.20-kg ball and of (b) the 7.20-kg ball if the collision is elastic. (c) Find the magnitude and ...
*October 12, 2014*

**physics **

A 220-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 26.6° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.863, and the log has an acceleration of 0....
*October 1, 2014*

**physics**

I figured this out.. So basically you find the acceleration first V-Vo/t= 59.4-0/14.1 = 4.21m/s2 then, you find the apparent weight by multiplying 66.7*(9.8 + 4.21)= 934.47N
*September 30, 2014*

**physics**

A rocket blasts off from rest and attains a speed of 59.4 m/s in 14.1 s. An astronaut has a mass of 66.7 kg. What is the astronaut's apparent weight during takeoff?
*September 30, 2014*

**business**

yes
*September 29, 2014*

**Math**

and theta is between 0< theta< 2 pi
*September 29, 2014*

**Math**

solve: cot(2theta/3)= -sqrt3 Please help, I don't know how to start and how to set it up.
*September 29, 2014*

**physics**

A rocket blasts off from rest and attains a speed of 59.4 m/s in 14.1 s. An astronaut has a mass of 66.7 kg. What is the astronaut's apparent weight during takeoff?
*September 28, 2014*

**physics**

Damon, I honestly want to thank you for your precious efforts in helping students. I have a question regarding the equations you've set above. Could you clarify how to find FB please?
*September 27, 2014*

**physics**

The mass of a robot is 6930 kg. This robot weighs 2520 N more on planet A than it does on planet B. Both planets have the same radius of 3.01 × 106 m. What is the difference MA - MB in the masses of these planets?
*September 27, 2014*

**physics**

A ball is thrown upward at a speed v0 at an angle of 59.0¢ª above the horizontal. It reaches a maximum height of 7.5 m. How high would this ball go if it were thrown straight upward at speed v0?
*September 20, 2014*