Explanation:
Mg-2+C+4>Mg2C.
Here you divide the four by the two and transfer the two toMg. In reactions like this oxidation numbers are exchanged.
It's a plain, not a lever
Answer:

Explanation:
The period equation for a pendulum is given by:

and we know that T = 1/f, where f is the frequency, so we will have:

Now, we just need to solve this equation for L.


- g is the gravity in Bogota (g=9.78 m/s^{2})
- f is 10 Hz
- L is the lenght of the pendulum


I hope it helps you!