Answer:
The importance of international bureau of weights and measures are;
1. to bring unification of measurement system.
2. to establish and preserve fundamental international prototypes.
3. to verify national standards, etc.








<h3>☯ <u>By using formula of Lens</u> </h3>











<h3>☯ <u>Now, Finding the magnification </u></h3>





<h3>☯ <u>Hence</u>,

</h3>


Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 



