Friday

April 18, 2014

April 18, 2014

Total # Posts: 572

**Algebra**

That makes sense. Thank you!

**Algebra**

Can someone explain to me why the intersection of two infinite sets is not always an infinite set, but the union of two infinite sets is?

**social studies**

You have mrs kalinski

**grammar**

how do i know what words go with the predicate? In the sentence "She can read this story aloud to you," It seems to me that the predicate would stop at "aloud." I'm pretty confused thank you for your time and help

**grammar**

what is the difference between a predicate and a verb? is a predicate a type of verb and if it is then how can i tell when it is just a verb and when it is a predicate

**Spelling**

it'll (it will) when'll (when will) who'll (who will) when's (when is) who's (who is) what's (what is) where's (where is) how's (how is) why's (why is) haven't (have not) can't (can not) won't (will not) don't (do not) shan&#...

**science EASY but help plz**

Solve: A jar contains 45mL of corn syrup whose mass is 41.4g and 90mL of glycerin whose mass is 75.4g. Which liquid is on top? SHOW MY WORK? im not sure how to do that what math would i show?

**math**

what is mass?

**chemistry**

I was doing a spectroscopy problem, and on the NMR spectrum a peak at around 4.4 with 2 H says "exchanges with D2O". What does this suggest?

**biochemistry**

Where can I find information on decarboxylases, kinases, etc and their function? I look everywhere, but the only information I can find is on wikipedia...

**Chemistry**

Im's So confused about stoichiometry. My question is this use stoichiometric calculations to predict the mass of solid product fromed in the reaction from the knwon mass of sodium hydrogen carbonate used. Balenced equation: 4NaHCO3 = 4Na + 2H2O + 4CO + 3O2

**Chemistry**

Choose the true statements regarding the charge-minimized Lewis structure(s) of the BrO2- ion. (selet all that apply) a. There is only one charge-minimized structure for this ion. b. There are two charge-minimized resonance structures for this ion. c. The formal charge on the...

**algebra**

9b^2-(-4b)^2 is this 9b^2+4b^2 or 9b^2+16b^2?

**MATHS**

In a quadrilateral ABCD, Angle A = 120 degrees, Angle B = 140 degrees. The bisectors of the angles C and D meet at the point Y. What is the size of the angle DYC?

**math-algebra**

thank you drwls!!!!!!!!!!!!!

**math-algebra**

x=3y-4 2x-y=7 solve as a set/substitution.

**algebra**

in y= mx+b m=rise/run what is b for?

**Algebra**

4x+y=3 find the slope using the slope form formula y=mx+b slope=rise/run

**Physics**

I get as far as 1/Do + 1/-1.58 = 17.167, but I'm not sure what my next step is.

**Physics**

-An object whose height is 5.8 cm is at a distance of 9.5 cm from a spherical concave mirror. Its image is real and has a height of 9.2 cm. Calculate the radius of curvature of the mirror. I got 0.1165 m for my answer. -How far from the mirror is it necessary to place the abov...

**Physics**

My homework site does not accept 1.8 m. What are we doing wrong??

**Physics**

At 10:00hrs a 1.5- m-long vertical stick in air casts a shadow 1.4 m long. If the same stick is placed at 10:00hrs in air in a flat bottomed pool of salt water half the height of the stick, how long is the shadow on the floor of the pool? (For this pool, n = 1.44.) I know this...

**Physics**

What is the smallest a flat mirror can be while still being able to see your full reflection? I need to show my work/explain. Can anyone help me?

**Pre-Algebra**

i can help

**Physics**

A 86.0 kg person steps into a car of mass 2500.0 kg, causing it to sink 3.0 cm. Assuming no damping, with what frequency will the car and passenger vibrate on the springs? Here is what I do. I take the mass and set it equal to k*x to get k, then divide by 4. Then I add the 2 m...

**Physics**

N/m. I was doing it right all along, but the computer wasn't accepting meters as the correct unit.

**Physics**

My question had 2 parts: a) A 2.0 kg object oscillates with simple harmonic motion on a spring of force constant 580.0 N/m. The maximum speed is 1.0 m/s. What is the total energy of the object and the spring? Answer: 1.0 J b) What is the maximum amplitude of the oscillation? T...

**tom**

I'm pretty sure you use the equation "velocity = frequency x wavelength," where you use your wavelength and the velocity of sound in air, which is usually around 345 m/s.

**Physics**

Anything else?

**Physics**

When you release the arm of a trebuchet and the projectile is released, I know that energy is lost/wasted. Can someone give me some good examples of what happens to this energy?

**Physics**

N/m I figured it out!

**Physics**

A lead ball, with an initial temperature of 25.0oC, is released from a height of 96.0 m. It does not bounce when it hits a hard surface. Assume all the energy of the fall goes into heating the lead. Find the temperature (in degrees C) of the ball after it hits. Data: clead = 1...

**Physics**

In a certain process, 2.11x10^5 J of heat are supplied to a system and at the same time, the system expands against a constant external pressure of 6.89x10^5 Pa. Given that the temperature of the system does not change, find the increase in volume of the system. Do I need to f...

**Physics**

The burning of gas in a car produces about 12,600 kJ/gallon of energy. If a car averages 35 km/gal when driving 90 km/hr, which requires 18.5 kW, what is the efficiency of the engine under those conditions? ...please help?

**Physics**

I don't use the mass at all then?

**Physics**

A steam engine's boiler completely converts 155 kg of water to steam. This process involves the transfer of 3.5 x 10^8 J by heat. If steam escaping a safety valve does 1.76 x 10^8 J of work against the outside atmosphere, what is the net internal energy of the water-steam ...

**Maath**

if you roll a fair number cube 30 times ,how many would you expect to roll a number that is a multipule of 3.

**Astronomy**

Great, thanks. :)

**Astronomy**

If a space probe were sent into orbit around the sun that brought it as close as 0.5 AU to the sun and as far away as 5.5 AU, what would its orbital period be? Can I use Kepler's 3rd law for this? I'm not sure how to take into account both AUs...

**Astronomy**

N/m I figured it out.

**Astronomy**

If you lived on Mars, which planets would describe retrograde loops? Which would never be visible as crecent phases?

**English**

in chapter 6 what is 1)contrast the attitudes of jack and ralph to the news of the beast. 2)what us the beast from the air? and 3) what is meant by "Piggy hung about near for all his brave words?"

**pre-calc**

what does multiplying a complex number by a real number do to its polar representation?

**precalc**

factor: (x-1)^1/2 - x(x-1)^-1/2 ive tried multiple different ways to firgure it out, but i cant seem to get too far in my work, i just dont know where to start.

**chemistry**

How does the cm^3 cancel out I'm multiplying 7.87g/cm^3 by 16.4cm^3?

**chemistry**

So it would be: 7.87cm^3 * 16.387064 cm^3/1in^3? Wouldn't it be the other way around with 1in^3/16.387064cm^3?

**chemistry**

If the density of a substance is 7.87 g/cubic cm, convert this density to g/cubic inches.

**Pre-Calculus**

rewrite using radicals and rational numbers Cos 3(pi)/8

**Physics**

How do the mainsail and the jib of a sailboat help the boat sail? What do these two sails have to do with force?

**Physics**

My class is making sailboats out of styrofoam. Basically we are given a block of styrofoam, some plastic bags/wooden dowels for the sails, and a little piece of metal for the keel that is either extremely light or a little heavier, whichever we want. When we have finished cons...

**Physics**

An archer shoots an arrow that leaves the bow at an angle of 42 degrees above the horizontal. The arrow hits a target located 135 m away and 23 m above the height from which the arrow was shot. Given that the mass of the arrow is .125 kg and that it remained in contact with th...

**Physics**

An archer shoots an arrow that leaves the bow at an angle of 42 degrees above the horizontal. The arrow hits a target located 135 m away and 23 m above the height from which the arrow was shot. Given that the mass of the arrow is .125 kg and that it remained in contact with th...

**physical science**

Hydroelectricity

**Biology**

I'm so horrible at biology so help is appreicated; "The following experiment is to test the limits of cell population growth. Cells were grown in six flasks under different conditions. Eash flask contained a nutrient broth of the same concentration. The table below sh...

**Psychology**

I had to do a learning project in Psych. For my project I taught myself to make my bed every day using operant conditioning. If I made my bed within 5 mintues of waking up, my mom would give me 5 dollars. I know this is positive reinforcement. However, I failed to make my bed ...

**Physics**

During World War 2, there were some cases where the crew fell out of burning aircraft without a parachute and survived the fall. Assume that the crew member reached a constant terminal speed of 128.3 km/hr prior to hitting a stack of loose hay. If the crew member can survive a...

**Physics**

A flea pulls on a puck with force 7 microN at an angle of 30°. Another flea pulls on the puck with force 2 microN at an angle of -60°. a) What is the magnitude of the net force on the puck? (I got 7.28 uN) b)At what angle is the net force? ( I got about 14.07 deg) c) A...

**Physics**

Thanks. :)

**Physics**

A car traveling at a constant speed of 125 km/hr passes a trooper hidden behind a billboard. One second after the speeding car passes the billboard, the trooper sets in a chase after the car with a constant acceleration of 2.7 m/s^2. How far does the trooper travel before he o...

**Physics**

A 2.6 m long, 16 kg piece of plywood is sitting on a pair of sawhorses. The sawhorses are .3 m from the left end and .5 m in from the right end of the plywood. A 4 kg circular saw is sitting 1 m in from the left end of the plywood. How much force is each sawhorse applying? Ass...

**Physics**

How much torque is applied to a bicycle wheel whose radius is 0.40 m in order to accelerate the 15 kg bike and 78 kg rider at a rate of 3.4 m/s^2? I'm totally lost on this one. Which equation do I need to use?

**Physics**

I still cannot solve this problem: Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the craft literally weigh...

**Physics**

I've tried this several times, and I keep coming up with 43765.73 km, which is not correct. ???

**Physics**

Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the craft literally weightless. Take the distance between th...

**Physics**

Oh you're right, I forgot that step. So 5.07E-12 N is the net force with both balls.

**Physics**

(6.67E-11)(2.16)(0.0088) / (0.5068)^2 = 4.94E-12 N Is that correct?

**Physics**

Two 2.160 kg crystal balls are 0.870 m apart in the vertical direction. Calculate the magnitude of the gravitational force they exert on a 8.80 g marble located 0.260 m horizontally out from the center of a line that intersects the centers of the balls. (For your own knowledge...

**Physics**

Ohhh I see now! Sorry, I just wasn't understanding before. Thanks. :)

**Physics**

Right. But w/o knowing the actual mass of the earth and moon, only the ratio, how can I do this?

**Physics**

Suppose that the ratio of the Moon's mass to the Earth's mass is given by 1.200E-2 and that the ratio of the Moon's radius to the Earth's radius is given by 2.700E-1. Calculate the ratio of an astronaut's Moon-weight to Earth-weight. Now it seems like this ...

**Physics**

Actually, that just made me even more confused. I still don't know what I'm supposed to use as the distance from the spaceship to the earth. Thanks, tho.

**Physics**

Ok I understand that. But what is the distance from craft to earth?

**Physics**

Oh wait...do I need to use F = GM1M2/d^2?

**Physics**

Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the craft literally weightless. Take the distance between th...

**Physics**

Great I got it, thanks for all your help.

**Physics**

My last problem for the day: A) The centers of two 11.00 kg spheres are separated by 0.09 m. What is their gravitational attraction? I got 9.96 x 10^-7 N. B) What is the ratio of this attraction to the weight of one of the spheres (at the surface of the Earth)? I'm sure th...

**Physics**

Oh ok I see. Well, my online homework site would only accept it as postive, but it has been known to make errors before.

**Physics**

I tried both of the ways and got the same answer. However, the answer I got using bobpursley's equation got me -5.11E-8, when it was really positive. Was there an error in that equation, or did I just mess up with the math somewhere along the way?

**Physics**

Three very small spheres are located along a straight line in space far away from everything else. The first one (with a mass of 2.43 kg) is at a point between the other two, 10.60 cm to the right of the second one (with a mass of 5.17 kg), and 20.70 cm to the left of the thir...

**Physics**

The Wall of Death in an amusement park is comprised of a vertical cylinder that can spin around the vertical axis. Riders stand against the wall of the spinning cylinder and the floor falls away leaving the riders held up by friction. The radius of the cylinder is 3.8 m and th...

**Physics**

This is the info for the problem: A block of mass M1 = 160.0 kg sits on an inclined plane and is connected to a bucket with a massless string over a massless and frictionless pulley. The coefficient of static friction between the block and the plane is ms = 0.52, and the angle...

**Physics**

Ahhh ok that was what was wrong. Thanks a ton. :)

**Physics**

A youngster shoots a bottle cap up a 15.0° inclined board at 1.92 m/s. The cap slides in a straight line, slowing to 0.95 m/s after traveling some distance. If the coefficient of kinetic friction is 0.35, find that distance. I still get 0.315 m as the answer, but it's ...

**Physics**

Ok I got it, thanks. The last part is this: Suppose the coefficient of kinetic friction between the block and the inclined plane is muk = 0.36. If M2 = 217.1 kg, what is the magnitude of the acceleration of M1? Which equation am I using for this?

**Physics**

That's right. Now it asks for the minimum value of M2 for which the system will remain at rest. Do I still use mgSinTheta-mg*mu*CosTheta?

**Physics**

A block of mass M1 = 160.0 kg sits on an inclined plane and is connected to a bucket with a massless string over a massless and frictionless pulley. The coefficient of static friction between the block and the plane is ms = 0.52, and the angle between the plane and the horizon...

**math**

49% is 0.49 as a decimal, and 80% is 0.80 as a decimal. 0.49 x 0.80 = 0.392, or 39.2%

**Physics**

Using 21.6 as the angle for both cos and sin, I come up with 33.91, which is the incorrect answer. Am I still doing something wrong?

**Physics**

Why is it sin and cos of 23.5? I thought the angle was 21.6...

**Physics**

Do you come up with an answer of 33.91? Because that's what I get.

**Physics**

Ok I understand that part. Now it asks for the minimum magnitude of F that will start the block moving up the plane, and the magnitude of F that is required to move the block up the plane at constant velocity. Is it a similar process for both?

**Physics**

A block weighing 70.7 N rests on a plane inclined at 21.6° to the horizontal. The coefficient of the static and kinetic frictions are 0.23 and 0.12 respectively. What is the minimum magnitude of the force F, parallel to the plane, that will prevent the block from slipping?...

**Physics**

I've entered this into the computer, but it says it's not right. Hmmmm...

**Physics**

I keep getting 0.315 m, but that's not right. What am I doing wrong?

**Physics**

A youngster shoots a bottle cap up a 15.0° inclined board at 1.92 m/s. The cap slides in a straight line, slowing to 0.95 m/s after traveling some distance. If the coefficient of kinetic friction is 0.35, find that distance. So I get that (1/2)MV^2 = MgX*sin 15 + Mg*muk*co...

**Physics**

A youngster shoots a bottle cap up a 15.0° inclined board at 1.92 m/s. The cap slides in a straight line, slowing to 0.95 m/s after traveling some distance. If the coefficient of kinetic friction is 0.35, find that distance. So I get that (1/2)MV^2 = MgX*sin 15 + Mg*muk*co...

**Physics**

What is V, in this case?

**Physics**

A youngster shoots a bottle cap up a 15.0° inclined board at 1.92 m/s. The cap slides in a straight line, slowing to 0.95 m/s after traveling some distance. If the coefficient of kinetic friction is 0.35, find that distance. I still don't quite understand this one. How...

**Physics**

Ahh ok, I didn't realize the masses cancel out. But of course you're right. That really was easy. :)

**Physics**

A hockey puck is sliding across a frozen pond with an initial speed of 6.5 m/s. It comes to rest after sliding a distance of 7.6 m. What is the coefficient of kinetic friction between the puck and the ice? I know this one is not that difficult. However, I can't seem to get...

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