Tallest structures in the world

   The tallest man-made structure in our world  is Burj Khalifa, a skyscraper in Dubai that reached 828 m (2,717 ft) in height on 17 January 2009. The  CN Tower  in Toronto, Canada, standing at 553.3 m (1,815 ft), was formerly the world's tallest completed freestanding structure on land. Opened in 1976 and unfortunately it was surpassed in height by the rising Burj Khalifa on 12 September 2007.  and of course there are some others pretty tall structures in our world that are not mentioned above.

but if you observed these structure more closely, it was very obvious that they all ave one thing in common, that the base of their structures are always wider than their tops. in fact, most of these buildings are in a  somewhat   cone shape , which help them to stand. Tomorrow our Teacher, Mr.Chung will ask us to build a structure with only newspaper. and the highest will won, what a exciting class and what a waste of newspaper.

Questions on projectile Motion

    Our interesting, somewhat handsome, evil physic teacher Mr.Chung asked us to blog some of the projectile motion questions he gave us. there are 5 type of projectile motion in total for grade 11 physic according to Mr. Chung's word. some of the questions are really straight forward, and some are little tricky to handle. but i don't think Mr. Chung will leave us alone with only this amount of work, this might only be the beginning............
Anyway, here are some of the answers to the questions on the projectile worksheet.
more questions will be posted afterwards :

How to build an egg glider?.

A new project  was given to us by Mr. Chung, that is, building an egg glider that is strong enough to protect the egg from breaking if the egg are going to be dropped to the ground from second floor.  Mr. Chung said that this will be helpful for us to learn kinematics and motion. but the task he gave us seems to be impossible to complete. we will only  be given 25 straws, one sheet of newspaper, and a limited amount of tape to complete this egg glider within 70 min. but since we are human, the most intelligent species and the ruler of this planet for over 6000 years . we can always solve the problem by using our brain. so, after 70 minuets of work, our group come a out a wonderful egg glider which are perfect in everything except of that it's ability to protect the egg is still unknown.
Anyway, here  are materials we used to build our egg glider:
you will be surprised when you see our outcome~

     Mr. Chung asked us to blog one of our homework on the blog,  which I think is totally unnecessary, to show my "creative" writhing on the blog and for everyone to see. anyway. here is my work on the following question : Page 72 #54,#56#58,#60,#62,#62. six question in total, right?

    If you see any mistake, it would be very helpful for you to kindly inform me and show me the correct method. Thank you and your action will be appreciated.

    Also , due the tectonically difficulties, some pictures are up-side down. so please cop and paste them into Word documents and read if you want to read about the details. sorry about the inconvenient.

    Here are the Answers :

Kinematics Graph Translation (of the lab results).

         Here is the translation of the graph of our physic lab, it is only a rough draft on the original graph. Mr.Chung said this is a kick off on our lab report. then, I am so proud of myself that i start doing my lab.

Here are the result(with the translation on the graph):
Please remember: the translations is for the graph before the that graph.

Walking the Graph Experience

We did a lab on matching the graph with a motion detector. it is harder than it looks.
 but it is a fun experience, also, this lab shows the difference between Distance-Time graph and Velocity-time graph. it is a interesting and helpful lab.

Here is some result of the lab:

RHR 1 & 2

Right hand rules are basically some rules about using your right hand to find out the direction of the magnetic field and the direction of the currents and forces,

right hand rule #1 : 
- the direction of the conventional current are indicated by the thumb of the right hand.
- the curved fingers point in the direction of the magnetic filed around the current.

right hand rule #2 : 
- the direction of the conventional currents are indicated by the curved fingers.
-the  thumb points in the direction of the magnetic filed within the coil. outside the coil, the thumb represents the North end of the electromagnet.