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Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 15862 letters have been answered. They are listed according to date.

You can read them to further your understanding of the subjects.

List of next 15 letters





Confusion about calculations Motion USA
Solenoid and electromagnet Physics Magnetism India
Give examples of using force Physics Force Malaysia
Alzheimer's resource Aging USA
Using adapter between plugs Physics Electricity New Zealand
Why is there a gap in a sound wave? Waves India
Can noise cancellation stop tinnitus? Sound UK
Can a person mess with your 6th sense? Senses USA
Why does an apple change color when cut open? Chemistry India
Voltage for vacuum pump Electricity New Zealand
Seeking permission to use image Magnetism Singapore
Getting rid of chronic pain Religion Buddhism Canada
I would like to cancel a transaction Finances UK
How fast is a magnetic impulse? Physics USA
Is time static? Physics Relativity USA

Next 15 letters


First 15 letters

Confusion about calculations


June 13, 2017


I follow you calculations up until the last part when you multiply the 6.28 * Square root of (0.2). I suspect it has something to do with the /sec/sec. could you explain a little further? Thanks for you time in this matter.

Jim - USA (28090)


The calculations go: 2 * 3.14 * ?(2/9.8) = 6.28 * ?(0.2) = 6.28 * 0.45 = 2.8 sec.

Since 2/9.8 = 0.204, I rounded it off to be 0.2. Since this caused some confusion, I updated the page to show 0.204 and changed 0.45 to 0.4517. The answer is 2.837 or rounded off to 2.8 sec.

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Solenoid and electromagnet


June 13, 2017


Why solenoid is used for making electromagnet

Nishant - India (28091)


A solenoid is an electromagnet without the iron core in it. The solenoid can be used to pull a core inside it.

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Give examples of using force


June 12, 2017


Name one examples when force can stop motion.

Name one examples when force can change the shape and size of an object

Nicholas - Malaysia (28088)


You can push on a rolling cart to stop its motion.

You can compress a foam rubber ball to change its size and shape.

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Alzheimer's resource


June 12, 2017


My grandmother on my mom's side suffered from dementia in her last few years.

It was extremely hard on my mom, who was the one sibling who lived near enough to take care of her. There were days when she was so sweet and thankful to my mom for loving her and being there for her. Then there were those days when grandma seemed to absolutely hate my mom and not know who she was. Yet my mom was still loving and dedicated, caring for her until she passed.

With that on my mind, I was looking for helpful resources to include in an upcoming roundup on caring for and understanding loved ones with Alzheimer's and other forms of dementia, when I found your resources page. Thank you for your effort in keeping those resources up to date.

Just thought I’d share this in-depth guide to improving safety for loved ones with Alzheimer's or Dementia who are living at home like my grandma did, so you can include it in your page.
How to Make a Home Safe for a Loved One with Alzheimer’s or Dementia

Either way, thank you for your effort in keeping those resources up to date, and for supporting my goal of helping to make home a safer place for our loved ones who suffer from Alzheimer's or dementia.


Yvonne - USA (28089)


Thanks for the suggested resource. I added it to Healthy Aging Resources.

Best wishes in your efforts to make home safer for loved ones with Alzheimer's.

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Using adapter between plugs


June 11, 2017


can I use an appliance from south Korea - 220v in New Zealand 230v ? from your chart it would also appear that the frequency will be different also will this cause problems? thirdly the plug types are different is it ok for an electrician to change the plug from c to l

Tina - New Zealand (28086)


The voltage difference should not affect things. However, a 60Hz appliance might perform slower with 50Hz. If there are timers or clocks involved, it might make a difference. It is good to check with the manufacturer website to see if things would work sufficiently.

An adapter plug could be used if the prongs are different. An electrician should be able to make the proper connections.

Best wishes for successful use of your appliance.

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Why is there a gap in a sound wave?


June 10, 2017


Why there is an gap between successive compressions and successive rarefactions?

Abhisheka - India (28082)


There is no real gap between compression and rarefaction in sound waves. The wave shape is a continuous sine wave. That means one half of the waveform is compression, followed by an instantaneous change to then become a rarefaction.

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Can noise cancellation stop tinnitus?


June 10, 2017


I have tinitus but am luky as my mind can cancel it out, BUT many people cannot and it drives them mad
can this technology be used for this

len - UK (28083)


It would be nice if noise cancellation would help out, but unfortunately it only cancels external noises. Tinnitus is the perceptions of sounds in your inner ear. There are some medications that can help. See Tinnitus

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Can a person mess with your 6th sense?


June 10, 2017


Can A person mess with your six Sense if so how would you act

Michael - USA (28084)


Our definition of the sixth sense is precognition or being able to sense future events. It is different than being able to read or affect minds.

It is difficult or even impossible for others to mess with your senses, except by some trickery. You can usually tell if you are being tricked.

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Why does an apple change color when cut open?


June 9, 2017


Why apple turns into red colour after cutting into slides?

Maddakam - India (28081)


Apples start to oxidize once they are cut open. That is the reason the colour changes.

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Voltage for vacuum pump


June 7, 2017


hi, i'm looking to buy a vacuum pump from china rated 220v-50hz.can i use it in new zealand which is 240v-50hz with no problems?it has the same plug connection as nz.

dave - New Zealand (28078)


AC voltages vary by about 10% from the listed value. So using a 220V pump at 240 volts should work fine.

Best wishes with your new pump.

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Seeking permission to use image


June 6, 2017


To Whom It May Concern,

I am Christine from the Copyright team of Kydon Learning Systems Institute. My team consists of myself as the Learning Designer and Project Manager, Bing Ying.

We are writing on behalf of Dr So Ping Lam from the School of Electrical and Electronic Engineering, in Nanyang Technological University, Singapore, who teaches EE3010, Electrical Devices and Machines.

As the appointed Content Partner, we are responsible for converting the course EE3010, into a blended learning course which video lectures will be produced and uploaded into NTU’s learning portal. The image on "right-hand rule for electric wire" which we are seeking copyright clearance will be used in the video lectures and students’ lesson materials. Proper citation using APA style will be used for each image to acknowledge your work. The blended course will be launched in January 2018. There will be about 150 undergraduate students who will have access to the learning portal to participate in this course.

We are flexible about restrictions regarding modification and use, so feel free to let us know about it.

Alternatively, if we do not receive your reply, we will add the citation (to mention that the source taken from your website) in our work.

We look forward to your favourable response in granting us the permission to use the image.

Thank you and hope to hear from you soon.

Yours sincerely,

Christine - Singapore (28076)


You have permission to use the "right-hand rule for electric wire" image in your blended course with no copyright or modification restrictions, as long as it includes the proper citation.

Our website is intended for the advancement of learning and education.

Best wishes for success in your blended learning project.

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Getting rid of chronic pain


June 4, 2017


Can you please explain what the 8 attitudes or paths really mean? What is meant by right view, right speech, right intention, etc.etc. I would also like to know how cessation of desires would end chronic physical pain.As an example someone who is born with a painful condition who is still too young to have formed any desires or attachments in life?

Joe - Canada (28073)


You can see explanations of the items in Noble Eightfold Path in Buddhism. They provide the recommended attitudes and conduct for a good life.

Desires and attachments in life seem to concern the mental and emotional conditions. For example, a person with chronic pain should not be envious of those without the pain. Some meditation practices can help a person alleviate pain. However, medication practices still are usually required.

Best wishes for both physical and spiritual health.

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I would like to cancel a transaction


June 3, 2017


i would like to cancel a transaction i made with Newchic

william - UK (28071)


You can check with PayPal UK to see their procedures.

You also should be able to cancel through Newchic online. And finally, you should be able to cancel payment through your credit card company.

Best wishes in cancelling your transaction.

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How fast is a magnetic impulse?


June 3, 2017


Have the effects of magnetism (attraction-repulsion) ever been quantified into speed? How fast is a magnetic impulse?

James - USA (28072)


Magnetic, electrical, and gravitational impulses all move at the speed of light. Typically, a magnetic disturbance will cause an electrical disturbance, resulting in an electromagnetic wave, which also travels at the speed of light.

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Is time static?


June 2, 2017


Love your site, Thank You!

Subject: Relativity/Time
We humans understand time as past, present and future.
The Past is our Memory
The Present is our Current Condition
The Future is our Expectation

Is it possible that Time is static?

We exist in a series of static universes that we register as the duration or "flow" of time.
Even at Planck time there is duration.
Duration is change in the Universe.
By splitting any change into time segments, every change has a beginning, a duration and an ending.
Even the emission of a photon.
It is a static photon, it starts to move, continues to move and stops moving when acted upon or reaching the desired destination (Planck Length).
During the moment when it starts to move there is duration between its static point and its next static point.
There is even duration between the change of static points. Like a buildup to change similar to a potential charge of time. I'll call it a Duriton.
Duritons occur faster than can be measured by our technology. Just because something can't be measured doesn't mean it can't exist.
Our lives are a series of duritons that we register on a massive scale to simulate continuity.
Is it safe to say that we exist in a constant flow of individual duritons, remembering the past as the present?

Thank you.

tMic - USA (28069)


The whole concept of time is difficult and complex.
As far as humans go, the sensing of time seems to vary with age. See Sensing Time. Thus, is time different for different people?

At the quantum level of matter, movement is in "quantum jumps" instead of being continuous. Likewise, since time is related to motion, it too could be in quantum increments. Thus, you could think of time being static in between those jumps. Your idea of a "Duriton" might fit within that area.

In some theories, time is considered a fourth dimension. It can curve just as space can curve.

Keep up the good work in pondering these issues.

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