| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the value of acceleration due to gravity g with different lengths of a pendulum.
Tip 1: The oscillation time of a simple gravity pendulum is $T=2\pi\sqrt{\frac{l}{g}}$
Tip 2: Move the information to $(T^2,l)$ –coordinate system.
Tip 2: Move the information to $(T^2,l)$ –coordinate system.
Answer: $9{,}9\ \frac{m}{s^2}$