Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 15704 letters have been answered. They are listed according to date.
You can read them to further your understanding of the subjects.
|5^6 times 8^6||Algebra||USA|
|Need to update home voltages||Physics||Electricity||USA|
|Can we use paypal in Myanmar?||Finances||Myanmar|
|Change frequency of LED light||Physics||Electricity||USA|
|Pressure points in foot reflexology||Health||Philippines|
|Using CO2 for supercritical extraction||Physics||Matter||USA|
|Reducing aerodynamic drag||Physics||Friction||Uganda|
|Correcting number of Jupiter's moons||Astronomy||USA|
|Motivations for good grades||Grades||USA|
|Superhero trying to outrun villan||Physics||Force||UK|
|Wore a PIG pin||History||USA|
|Recommending mesothelioma resource||Health||USA|
|Weight of two containers of water||Physics||Fluids||Egypt|
|Calculating speed of light for spectral line||Physics||Ireland|
5^6 times 8^6
January 31, 2017
hi, i have a question that is 5 to the 6th power times, 8 to the 6th power... how do i do this i asked everyone and they don't know how
noelle - USA (27847)
5^6 (5 to the 6th power) times 8^6 = 40^6 (40 to the 6th power).
(5^6)*(8^6) = (5*5*5*5*5*5)*(8*8*8*8*8*8) = 40*40*40*40*40*40 = 40^6
In general, (x^a)*(y^a) = (xy)^a
Need to update home voltages
January 30, 2017
On your page AC Wiring I encourage you to change all instances of "110" to "120" when referring to household voltage, since it is set (in the US) to 170 Vp, which ends up being approximately 120 VACrms.
Noji - USA (27841)
Thanks for pointing that out. Although 110 VAC is often used, the actual average between 110 and 120 is 117 VAC. But 120 is more commonly used. I changed the pages on AC from 110 VAC to 120 VAC.
I also updated the higher voltage from 220 to 240 VAC.
Can we use paypal in Myanmar?
January 30, 2017
Can we use paypal in myanmar
Ch - Myanmar (27843)
Apparently PayPal had been blocked on Myanmar, but it is now available. One site giving information is Payment from Myanmar with Visa. There are other sites also giving advice.
Check the PayPal site on service in Myanmar for some information.
Best wishes in using PayPal.
Change frequency of LED light
January 29, 2017
How can I change the frequency of an LED lifght?
Chris - USA (27836)
Right now, LEDs come in only three colors: red, green, and blue. A combination of them is a white LED.
Each color has a specific electronic configuration. Unfortunately, engineers have not found a way to vary the output frequency of an LED.
Pressure points in foot reflexology
January 29, 2017
1. what are the pressure points in foot reflexology?
2. what are their functions in each pressure points?
Jesus Ramon Neopolo - Philippines (27837)
I don't have the specific pressure points. You can check the various Resources near the bottom of the Reflexology page.
Best wishes for your work in reflexology.
Using CO2 for supercritical extraction
January 29, 2017
I would like to discuss some commercial uses for Dry Ice and it's conversion to Co2 for supercritical extraction.
Please let me know if you are available to discuss.
Thank you in advance,
Gary - USA (27838)
Dry ice is a convenient source of CO2. Allowing the gas from the dry ice to heat to about 31 degree C should help in the supercritical extraction process.
I hope that helps. Unfortunately, I am not an expert in this field.
Best wishes for success in your work.
January 28, 2017
1. Two objects attract each other with a force of 1×10^-8 N when separated by 20 cm. If the total mass of the objects is 5 kg what is the mass of each?
2. A spacecraft is on a journey to the moon. At what point between these two bodies does the gravitational force exerted on the spacecraft by the earth exactly balance gravitational force divided by the moon? At this point what is the net gravitational force on the spacecraft? assuming no other gravitational forces act.
I'd really love some help figuring these out!! Thank you!
Emily - USA (27831)
In the gravitational force equation, let "m" equal the mass of one object and "5 - m" be the mass of the other object. Thus, the equation is:
F = G(m)(m-5)/R^2
Thus: F(R^2)/G = m^2 - 5m
Use the quadratic formula to solve for m.
Note that R must be in meters.
See Law of Universal Gravitation for more information.
The second problem is solved by using the forces from the Earth and from the Moon on the spacecraft: GmM/r^2 = GmE/R^2
where m is the mass of the spacecraft, M is the mass of the Moon, r is the distance from the Moon to the spacecraft, E is the mass of the Earth, R is the distance from the Earth to the spacecraft. Also D = r + R the distance between the Earth and the Moon. That involves a lot of Algebra.
The net force is zero, since the gravitational forces cancel out.
I hope that helps.
Reducing aerodynamic drag
January 28, 2017
how to reduce aerodynamic drag
fatmil - Uganda (27833)
Usually, the shape of the object determines much of the aerodynamic drag. Streamlining can reduce that drag. Also, surface conditions can reduce some of the drag.
See Factors in Changing Fluid Friction for more information.
Correcting number of Jupiter's moons
January 24, 2017
On your article about the Earth's Moon, you said the Earth has one Moon and Jupiter has 9 moons. This is incorrect, NASA has recently discovered that Jupiter has 67 moons! I believe the number is up to 67 now. Up until a few years ago, they knew it had at least 63 moons. Galileo discovered 4 of them in the early 1600s. I can only see 5 of them with my modern day, powerful telescope.
David - USA (27823)
Motivations for good grades
January 20, 2017
I understand that many students are motivated in their school work to make their parents happy or prevent them from being angry but this is entirely external motivation. Nothing about this is motivation from inside the student. Nothing about this is visionary and external motivation is not necessarily a useful skill to have is it relies entirely on environmental factors. For these, I don't believe you should promote this type of motivation.
Carter - USA (27816)
Reasons to Seek Good Grades not only states that one external motivation is to please the parents, but it also gives internal motivations of satisfaction from proving yourself and being able to get into college.
Superhero trying to outrun villan
January 18, 2017
Hi there, I am researching for a comic book and was hoping you could answer a question I have. If an object accelerates in one direction (a) then suddenly reverses applying the same force in the opposite direction (b), is it possible that if travelling fast enough the sudden change in direction (a to b) would have a spring board effect increasing the acceleration and overall speed when continuing in direction (b)? How fast would the object need to be moving? This scene will be set in space and has a superhero character that is trying to find a way of outrunning his counterpart. Many thanks.
Karl - UK (27814)
Acceleration means that the superhero is continually increasing in speed. This could happen until he reached the speed of light.
If a the same force was applied in the opposite direction, the superhero would slow down until he stopped and then started to accelerate in the opposite direction.
It would be better to suddenly accelerate in a sideways direction, which would fool the villain, who would continue going along until he adjusts his direction of motion.
I hope that helps. Best wishes for your comic book.
Wore a PIG pin
January 17, 2017
i was a police officer during this time for the city of Kankakee which was a racist dept and we were issued a tie pin with a pig in the middle and words around it said "Pride Integrity Guts. I still have that pin.what happened during my time there you would not believe.
dennis - USA (27811)
Thanks for sharing your experience. It was good that the police forces turned what was supposed to be an insult into a positive statement.
I see that some of the recent demonstrators have been calling the police "pigs" again. They could stifle that by wearing pins like you had back then.
Recommending mesothelioma resource
January 16, 2017
My name is Virgil Anderson, and I’m a cancer patient at NCI. I saw some information on your site about mesothelioma and asbestos, and I was hoping you had room for mesothelioma.net. The medical professionals behind mesothelioma.net got me into NCI, and have been responsible for my continued battle against mesothelioma. They sponsor The American Cancer Society, ALA, Make a Wish Foundation, MD Anderson and many, many more.
Please, if there’s anything you can do to help, let me know.
I appreciate your time in advance, and hope you’re off to a good start in 2017.
Virgil - USA (27809)
Thanks for the information. I checked an saw that I already have a link to mesothelioma.net. However, I moved it to a more prominent position.
Best wishes for a full recovery from your cancer.
Weight of two containers of water
January 16, 2017
Two containers one of them has water and small piece of wood and another one has only water which one is heavier ?
Misho - Egypt (27810)
If both containers have the same amount of water in them, then the one with the wood in it would be heavier by the weight of the wood.
However, if the containers were full to the top and the piece of wood was added to one of them, some water would overflow from the container. The weight of the overflow water would be the weight of the water displaced, such that both containers would then weigh the same.
Calculating speed of light for spectral line
January 15, 2017
Hope you can help us. We are trying to calculate the velocity of a wavelength using a line profile.
We don't know what we are doing :-(
We know the rest wavelength 36.4680 nm, the line centre is 36.462 nm and c.
The anwser we are getting is 299785064.75!!!
Can the velocity of the wavelength be near the speed of light?
What is the correct formula?
Thank you on behalf of the LYIT astronomy society.
Seamus - Ireland (27806)
You need to be exact in your terminology. The "velocity of a wavelength" is incorrect. You should be looking at the velocity of light for a given wavelength.
In space, the light travels at the same speed for all wavelengths. When the radiation is passing through a material, the speed varies according to the wavelength or frequency.
If the source of the light is moving, the speed of light remains constant, but the wavelength can shift according to the direction and velocity of the source.
The profile of a spectral line is affected by the various velocities of the particles emitting that specific wavelength. The Doppler Effect causes the slight shifts in wavelength from the ideal situation.
I hope that helps.
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