Blog posts with the tag physics | Interested In Everything

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Blog posts with the tag "physics"

Apologies for the huge hiatus between posts, but I tend to get a bit snowed under at this time of year.  Not only are we barreling down the hill to exams, the final year project students are getting panicky and again I’ve acquired the task of teaching the part-time crowd all about non-contact measurement (something I might return to at a later date, actually – it’s a really interesting subject and some of the stuff I used to be involved in back in the day was rather impressive, even if I do say so myself).  One of the subjects we touch on is interferometry – without going into a description that will probably be an entire post in itself, that’s essentially the creation of patterns of light using the phenomenon of interference (see my earlier post on Thomas Young for more information if you’re curious).  One of the applications of this fascinating bit of science is for the detection of gravitational waves.  I often get asked what these actually are and I’m afraid the short answer to that is that I don’t fully understand that bit of science myself!  However, I have to say that I was quite interested to read this report a couple of days ago.

Scientists believe that they have discovered direct evidence of the phenomenon of cosmic inflation.  Now, this research has yet to be officially published in a peer-reviewed journal, but if it turns out to be confirmed, then we may be closer to understanding of the immediate aftermath of the big bang and how our universe actually came into being.  I’m still trying to grasp the fundamentals of all this, but apparently, polarisation in cosmic background radiation has been discovered and this polarisation is the result of the formation of the aforementioned gravitational waves.

 

Now this is where my knowledge of physics starts to let me down, but I’ll be watching this story with interest – mainly so that I can try to grasp the basics of gravitational wave theory…

These are just a few basic rules that form a basis for our understanding of physics.

 

 

To  recap, the first law states that:

  • An object at rest tends to stay at rest, and will remain at rest unless acted upon by an external force.
  • An object in motion tends to stay in motion, with same direction and speed.
  • Motion, or lack thereof, cannot change unless a force acts to change the motion.

Any change in motion involves an acceleration, which brings us to Newton’s second law:

 

 

F=ma where ‘F’ is the net external force on an object, m is the mass of an object and ‘A’ is the acceleration.

This law allows us to compare results of the same force exerted on objects of a different mass.

If you exert the same force on two objects of a different mass, you will get different accelerations, or changes in motion. For example, the effect of a 10 newton force on a golf ball would be much greater than that same force acting on a truck. This is due to the differences in their masses.

 

Newton’s third law states that for every action (force) there is an equal and opposite reaction.

 

 

As you can see from the example in our video, forces are found in pairs. There are no isolated forces. A system cannot pick itself up into motion with purely internal forces, to achieve a net force an acceleration it must interact with an external force.

 

Any questions? Still not clear?  Feel free to ask me anything or share your comments below. I look forward to hearing from you.