Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 15795 letters have been answered. They are listed according to date.
You can read them to further your understanding of the subjects.
|Viewpoint on gravitation and Big Bang theory||Physics||Gravitation||Bangladesh|
|Helped me understand a difficult problem||Thanks||Physics||USA|
|When is separation zero distance?||Gravitation||India|
|Is sound bent toward the ground?||Sound||UK|
|Confusion about calculations||Motion||USA|
|Solenoid and electromagnet||Magnetism||India|
|Give examples of using force||Physics||Force||Malaysia|
|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|
Viewpoint on gravitation and Big Bang theory
June 19, 2017
Near about 14 billion years ago Allah/God the big bang and started evolution, now 7 divisible gravitation worlds.
“Gravitational worlds, they are moving or changing the orbit with their all family members depending on the nuclear of each other”. In this way- There has been incidence of full view of the universe at the very exact copy/invitation of the visible diagram solar system in the gravitation world. The universe has seven divisible, the first one of which is unit and the rest six are collective. The collective six gravitation are three invisible and the rest three are visible. The visible gravitation worlds are stars, planets and minor planets. The invisible gravitation worlds are black holes of various energy levels, the first one of which is the primordial black hole or Allah/God of the nuclear fusion of the universe. There have been collective six gravitation divisible of the big bang in future from the big black hole or Allah/God. At the first phase or level of the divisible is the black hole of the nuclear fusion of the clusters of galaxies or black hole named quasar. The second phase gravitation world of the quasars in future are of the black hole named pulsar or nuclear fusion of the cluster of galaxies. The third gravitation world of the pulsars in future is of the last black holes or nucleus of galaxy or the nuclear fusion of the constellations.
New Discovery of the Universe: https://shahidurrahmansikder.wordpress.com/tag/god/
Pope: The most important news- about the God, Big Bang & Evolution at https://plus.google.com/104669722445739033329/posts/MQ9wQejCRLQ
Shahidur Rahman - Bangladesh (28099)
Thanks for the information and interesting viewpoint on gravitation.
Helped me understand a difficult problem
June 18, 2017
Thank you very much for this webpage. It helped me understand a difficult problem on my physics homework. I really appreciate you taking the time to make such a detailed and clear page.
Cheyenne - USA (28098)
I'm glad the material was useful to you. Best wishes for success in your studies.
When is separation zero distance?
June 17, 2017
1. Husband 70kg and wife 80kg are standing 1 mtr app art. At what they will come to zero distance by Gaby universilnal gravitational law ?
Prasad - India (28095)
The force is measured from the centers of mass of the two objects or people. Even when the husband and wife come into contact, there still is a separation between their centers, such they never will be at zero distance. See Gravitational Attraction Between Boy and Girl for more information.
Is sound bent toward the ground?
June 15, 2017
A simple question that I assume has a simple answer. I have assumed that noise travels in all directions from the source of the noise. Does it go in a straight line assuming no distortion by wind? So if noise from a road is reflected and absorbed by a sound barrier the direct undiluted transmission noise will be reduced. Assuming the above is correct, my question is will noise passing over a noise barrier just exhaust itself and not return to land or will it be forced down to the ground and house level by any force other than wind? What type of distance will be involved and will the situation be exactly the same with or without a sound barrier added close to the source of the road noise, please? Many thanks.
ROBERT - UK (28094)
Some of the noise from a road that passes over a wall or noise barrier can be redirected toward the ground due to diffraction of the sound at the edge of the barrier. See Diffraction Affects Blocking Noise.
The amount of the diffraction or bending is a function of the frequency of the sound. I'm sorry, but I don't have the calculations for determining the distances or bending of the waves.
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.
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.
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.
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.
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.
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.
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
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. 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. 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. June 6, 2017 To Whom It May Concern, 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. Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible. Click on a button to bookmark or share this page through Twitter, Facebook, email, or other services: The Web address of this page is: Please include it as a link on your website or as a reference in your report, document, or thesis.
Can a person mess with your 6th sense?
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.
Why does an apple change color when cut open?
Voltage for vacuum pump
Best wishes with your new pump.
Seeking permission to use image
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.
Our website is intended for the advancement of learning and education.
Best wishes for success in your blended learning project.
Questions and comments
Students and researchers
Where are you now?
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.
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.
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.
June 6, 2017
To Whom It May Concern,
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.
Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible.
Click on a button to bookmark or share this page through Twitter, Facebook, email, or other services:
The Web address of this page is:
Please include it as a link on your website or as a reference in your report, document, or thesis.