Answer:
If we double the length we will have:
![f'=(f)/(√(2))](https://img.qammunity.org/2022/formulas/physics/college/5cqcuf7s5jhusp2ffxhpginrbgc6gzaa8m.png)
Step-by-step explanation:
The equation of the angular frequency of a pendulum is given by:
![\omega=\sqrt{(g)/(L)}](https://img.qammunity.org/2022/formulas/physics/college/g27c9xyqqxznnxf2d1v4fdnsea573yhuyp.png)
Where:
- g is the gravity
- L is the length of the pendulum
By definition the period is:
![T=(2\pi)/(\omega)](https://img.qammunity.org/2022/formulas/physics/college/qx0nybteheffsooanvwix6nc5hae7ib7ha.png)
And frequency is 1 over the frequency T:
![f=(1)/(T)](https://img.qammunity.org/2022/formulas/physics/college/hmsyjm6dmaehvclc8qbyz3nhnx5uw6a4w8.png)
![f=(1)/(2\pi)\sqrt{(g)/(L)}](https://img.qammunity.org/2022/formulas/physics/college/13diytk6q0og5b29oy2yaxs9rlf4ljibqt.png)
Now, if we double the length we will have:
![f'=(1)/(2\pi)\sqrt{(g)/(2L)}](https://img.qammunity.org/2022/formulas/physics/college/kh3epetc76ipbpwmm4dzhh8c0oq5ayls7u.png)
![f'=(1)/(2\pi√(2))\sqrt{(g)/(L)}](https://img.qammunity.org/2022/formulas/physics/college/egqvayt6zim2egmj1ljbpbw4baz1ekld4i.png)
![f'=(f)/(√(2))](https://img.qammunity.org/2022/formulas/physics/college/5cqcuf7s5jhusp2ffxhpginrbgc6gzaa8m.png)
Therefore, the new frequency is the old frequency over √2.
I hope it helps you!