Se muestran los artículos pertenecientes a Marzo de 2017.

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    -  Watch the following video and later we will do a similar exercise all together :

       








-  Watch the previous video and the next ones you find below and try to do the following two exercises at home :  (you still have the videos with the solution in case you don’t know how to finish them).



1-    Problem 1 :

        a) A child throws just upright to the sky a little stone with a starting velocity of 6 m/s.  Find the time the Stone takes to reach the higher position.

        b) After that, work out the distance this stone goes over when it finally hits the ground at the end of its movement. How long does the Stone take to arrive again to the ground from its higher position on the top?.

        c) Work out the total displacement the stone does from the beginning to the end of its movement and the total time of this movement from the beginning to the end.


                         VIDEO 1 WITH THE PROBLEM’S SOLUTION.





2- Problem 2 :

    From the top of a skyscraper a stone is thrown in a straight line motion to the ground with a starting velocity of 2 m/s. if the stone takes 5 seconds to hit the ground, work out how high the skyscraper is.



                         VIDEO 2 WITH THE PROBLEM’S SOLUTION.

 (There is a mistake at the video because , as the Stone goes down some direction to gravity,  the starting velocity must have same sign as gravity, if I write minus sing for gravity I must write also minus sign for starting velocity.
   I should have written  - v0  instead of + v0 for the starting velocity. 
   So It must be written  :       0 = h - v0.t - 1/2.g.t2     ).

               Then the skyscraper’s high is :  h = 10 + 122’5 = 132’5 m







    Once you have tried to do these exercises and watched the videos, will you do a few more similar exercises next Friday in class. Then it is important you do at home the suggested activities on this article 118.


 DON’T FORGET TO DO THIS AT HOME!!!














   - Now that you have watched all these videos and last friday you have also tried a few more similar exercises in class, try now a few more ones like that at home as homework :


   Do exercises 43, 27, 58 and 59 from your book and have them ready on Monday.




                          
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  -  Let's look the following link up in order to learn about circular motion :


 
                                                           CIRCULAR MOTION THINGLINK.





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   - Try to do this exercise. If you cannot achieve it, watch the video and look at and listen to the explanation, but try first doing it without watching the video :



  > Exercise :

           A Stone is thrown from the top of a building with an initial velocity of 20m/s straight upward. The building is 50m high, and the Stone just misses the edge of the roof on its way down. Determine :

 a) The time needed for the Stone to reach its máximum height.
 b) The máximum height.
 c) The time needed for the Stone to return to the level of the thrower.
 d) The velocity of the Stone at this instant.
 e) The velocity and position of the Stone at time = 5 secons.


                                                      VIDEO WITH THE PROBLEM’S SOLUTION.





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     >    Fes click al següent enllaç, llegeix i fes els exercicis resolts :
       
     

                                                          LES ESCALES.




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 - This is a little drawing about the practice we have done of the uniform circular motion with our skates using a spinning movement at the playground.
    On friday we’ll check the times and data we have taken and will work out angular velocity and will talk about all of this.












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- At this article will be hung pictures and video about uniform circular motion practice we did yesterday using the skates :




   >  VIDEO.





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   - Check the following link to begin the next lesson about how forces act :




                                                 FORCES AND DYNAMICS.




















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             MAY THE FORCE BE WITH YOU !!!



- We’re gonna check first a nice exam example about this lesson and you’ll see how easy is handle or deal with this kind of exercises. You only have to put up with me or bearing me for a while :

(THIS EXERCISES HAVE BEEN TAKEN FROM THE OTHER PHYSICS TEACHER "ISABEL DE LLANÇA" AND HAVE BEEN VERY WELL PREPARED ).



                                     EXAM EXAMPLE 1          

                        EXAM EXAMPLE exercises 1,2,3 and 4 RESOLUTION           
                                           
                        EXAM EXAMPLE exercise 5 RESOLUTION

                        EXAM EXAMPLE exercise 6 RESOLUTION

                        EXAM EXAMPLE exercise 7 RESOLUTION

                        EXAM EXAMPLE exercise 8 RESOLUTION



 - You can follow a nice explanation video about NON CONCURRENT PARALLEL FORCES separated certain distance :










  -  After you’ve practiced and watched the different videos, try to do the following exercise by your own. Check previous videos as many times as you need to develope the exercise by yourself. In case you cannot achieve the problem’s solution you have the problem explained at the video below :


  > Exercise :

          A 15kg metal bar 6m long has two objects hanged at the opposite ends of the bar. At the left end of the bar hangs an 20kg object and at the right end of the bar the second 30kg object. Find where exactly the net force must be placed in order not to let the system fall. Work out the value of the net or balance force, the exact spot it must be placed, the direction and its sense.










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 - Watch the following videos about so many different kind of forces we can check :














  > LEVITRON.