Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 16200 letters have been answered. They are listed according to date.
You can read them to further your understanding of the subjects.
|Time to take echo to come back||Sound||Zimbabwe|
|Velocity and acceleration||Motion||Nigeria|
|What is AC?||Electricity||USA|
|Potential energy in motion||Gravity||Ghana|
|Update||School for Champions||USA|
|Mass and gravity||Gravity||USA|
|Coping with Tinnitus||Sound||Venezuela|
|Angle of sound||Sound||USA|
|Finding angle of sound||Sound||USA|
|Borrowed friends money||Character||USA|
|Sorry||School for Champions||Pakistan|
|Studying Physical Science||Physics||Kzn|
|Sensory overload||Mental Health||USA|
|Public speaking for 3rd grader||Speaking||USA|
Time to take echo to come back
June 9, 2021
A depth sounder on a boat sends out a pulse and listens for
the echo from the bottom. The water is 30 m deep. Calculate
how long will it take for the echo to come back
Talent - Zimbabwe (29974)
The speed of sound in water is about 1500 m/s (depending on the temperature of the water). The sound would take about 0.02 s to reach the bottom and another 0.02 s to bounce back. Thus, it would take the echo 0.04 sec to come back.
Velocity and acceleration
May 9, 2021
different between velocity and acceleration
Abdurrahmanmusa - Nigeria (29945)
Velocity is the speed of an object in a given direction. Acceleration is the change in the velocity over a short period of time.
What is AC?
April 21, 2021
What is AC?
Johnnie - USA (29921)
While DC is direct electrical current in one direction, usually from a battery source of power, AC stands for Alternating Current, where the direct goes back and forth. AC is created from an AAC generator or alternator.
Potential energy in motion
April 20, 2021
Can a body have a potential energy and yet be in motion?
Agboso - Ghana (29920)
The potential energy of an airplane depends on its altitude or distance from the ground. It keeps that potential energy when moving parallel to the Earth's surface.
When the airplane or any object falls toward the Earth, its potential energy is reduced according to its altitude at any given time.
April 11, 2021
Hi Ron, I am a former colleague from the HAC TOW-II days just saying hello.
John - USA (29908)
I've been seeing your Facebook posts and have been planning on contacting you.
I forgot that Hughes had been taken over by Raytheon. Also, I see you are doing well at Northrop.
After leaving Hughes, I got a job as a civilian with the Air Force at the Space Systems Division in Los Angeles, with the equivalent rank of Major, developing the Strategic Defense Initiative (SDI or "Starwars"). I then took over the TQM initiative for SDI. I published a TQM newsletter that was distributed throughout DoD. I also gave presentations on our work to various companies, including a presentation in the Pentagon to an audience of Generals.
Then I left the AF and moved back to Milwaukee, WI to help take care of my elderly parents. After they passed away, my wife and I moved to Lake Oswego, OR (just outside of Portland) to be near the granddaughters.
I've written a couple of nonfiction books and also run my School for Champions website.
I guess that's my life in a nutshell.
What have you been up to?
Mass and gravity
April 10, 2021
I am still confused as to mass and gravity. Say for example that the earth had 10% more mass (other things being the same) what would its gravity be?
Michael - USA (29906)
Thus can be a confusing issue.
Gravity means the force of attraction of a mass toward the Earth, according to the equation: F = mg, where g is the acceleration of the object due to gravity (g = 32 ft/s^2 or 9.8 m/s^2).
See Acceleration Due to Gravity is Constant.
"g" is based on the equation for gravitation F = GmM/R^2, as shown in the above reference. Thus if the mass of the Earth M was 10% greater, g would be 10% greater or about 35 ft/s^2.
I hope that helps.
Coping with Tinnitus
April 9, 2021
Hello, I have tinnitus. I have identified my tinnitus frecuency noice around 10MHz using a frecuency sound generator. So I am wondering if I could find a noice cancellation software that produce a wave cancellation frecuency but for a user specify frecuency. The user choose the frecuency and the software produces the cancellation wave. If this works, I could cancel the tinnitus noice I hear. Is this possible?
Franklin - Venezuela (29905)
Tinnitus is primarily an internal ailment. See Ringing Noise in Ears: Tinnitus
You may be able to mask the noise you hear with soft music or some other sound source, but since the sound is internal, sound cancellation probably would not work.
I hope you can find a solution or learn to cope with the annoying problem.
Angle of sound
April 8, 2021
Hi my question for you is I’m having trouble understanding how to find the angle between you and the line of sight of a sloth for example let’s say you’re 20 m away from around the track thought we need to thousand meters away if you Hewitt how do I get a find the angle that you have between you and the train? Thank you so much hope hope to hear back from you soon!
Cody - USA (29904)
I'm not sure I understand the configuration of your experiment. Perhaps if you give more details on what you want to do.
If an object is moving at some angle with respect to the line of sight, the sound frequency would be reduced by the cosine of the angle. If you know the given frequency and compare it with what you hear, you could fine the angle. However, that isn't easy to do.
I hope that helps somewhat.
April 6, 2021
Personal character influence the person's being liked or disliked. Discuss
Nshabire - Uganda (29901)
You are probably thinking about Social or External Character traits. (See Social Traits)
Personal character traits primarily concern you attitudes toward doing work for yourself.
Social character traits concern whether you help or harm someone else. Obviously, if you are helpful and positive toward others, they will be more apt to like you.
Finding angle of sound
March 28, 2021
Hello, I'm Cody Boys. I was curious how to find the angle between you and the line of sight of a moving source. In the article, it has an example where you are standing 10 meters from the road, and you hear the horn of the car when it's 50 meters away. I'm not quite understanding how to find that angle. The article has 10/50, which equals 0.2. Then it says the angle is 11.5 degrees. I don't understand how we're getting this angle from 0.2. I tried dividing 11.5/0.2, and the calculator always gives me random numbers that don't make since. I've tried looking at other sources of information, but none seem to have the answer I'm looking for. Does this formula also tell you how long it takes the frequency to shift to its highest to its lowest? The reason I ask is, when you hear a train pass on the railroad, the pitch change is sudden. But, when you hear the sound of an airplane or helicopter, the pitch seems to gradually shift, almost like it is in slow motion. I appreciate all of your time and helping me, it makes my day. Thank you!
Cody - USA (29893)
I just answered your other letter, but was not clear on the answer I gave. I should add an image for that example.
When the car is 50 m from you and 10 meters is the distance perpendicular to the road, the sine of the angle between you and the car (at that moment) is 10/50 = 0.2. Look up the inverse sine for 0.2 and you get about 11.5 degrees.
As a car or a train blaring its horn gets closer to you until it is perpendicular to you or 10 m away. At that position, you hear the exact frequency. Then, as it moves away down the track, the Doppler effect causes the frequency to lower.
The rate of charge in frequency has to do with the rate of change in the distance from you.
I hope this clarifies things a bit. It can be a confusion problem.
Borrowed friends money
March 2, 2021
Thank you for your message. I am 65, a widow and loaned good friends $10,000. They are 80 and I thought I was safe. After 6 months with no repayment or verbal message -- I confronted them. All they could say was "we don't have the money." I know I will never get a dime but let my guard down because of their age and I trusted them. Please remind people that these people come as true friends. Even when they have a statue of an angel in their front yard.
Marianne - USA (29874)
I'm sorry to hear that it looks like your "friends" probably won't pay you back. Lending someone a few hundred dollars is doing a good deed, but lending $10,000 should be considered a business transaction. In other words, payment conditions should be in writing and perhaps a lawyer should be involved before making the loan.
You might try asking for payments of something like $100 at a time, so perhaps you can some of your money back. You might even try to shame them into paying, by contacting their grown children about the loan.
Although these people may be short on cash, not even trying to pay you is a sign of very poor character on their part. At the very least, it shows that you are helpful and kind.
I hope your loan doesn't put a financial burden on you.
Best wishes on getting some money back.
February 27, 2021
Hope you are doing good!
I'm Bukhtawar and I work for an online digital marketing agency "Futuristic Artists".
I came across your site school-for-champions.com and got impressed with the persistent and efficient info and sensations on your site.
I was wondering if you do allow sponsored post & in-context link placement on already existing articles on your site? If yes, kindly reply to me with the best price per post.
Bukhtawar - Pakistan (29871)
Thanks for the offer. Unfortunately, we are not adding such items at this time.
Best wishes for success in your work.
Studying Physical Science
February 25, 2021
I would like to study Physical sciences,I would like to start from basic & more.
Jorah jassie - Kzn (29868)
I am glad you would like to study Physical Science. Starting points include:
Best wishes on success in your studies.
February 24, 2021
My 9-year-old daughter is autistic and she is very sensitive to noises and smells. I have written a guide that may be worth adding to your site. I have tried to make it very comprehensive, it discusses sensory overload and tips on how to manage it.
It can be found at:
I would love to know what you think.
Lisa - USA (29866)
Thanks for the resource. I added it to:
Best wishes to your daughter in coping with her autism.
Public speaking for 3rd grader
February 22, 2021
I am looking for public speaking lessons for my 3rd grader. Please let me know if you have any sessions planned.
Navyatha - USA (29863)
3rd graders usually aren't usually fearful of speaking to a group or class as are older students. The speech should be short, so it is easily memorized. When I was in the 3rd grade and had to recite a short poem to the church congregation, I was just told to speak loud and not mumble. I didn't know enough to be frightened, and it turned out fine.
There are a number of YouTube and other resources about 3rd graders speaking:
The thing is not to make a big thing about it. Let the child practice a few times in front of you, giving applause when finished.
I hope this helps to teach your 3rd grader about public or class speaking.
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