The document solves two problems regarding a simple pendulum: 1) Given the frequency and gravity on Earth, it calculates the length of the pendulum string as 0.17m. 2) It then calculates the periods of the pendulum on Earth (0.83s) and Mars (1.34s), explaining that the period is longer on Mars due to its lower gravity of 3.71m/s2 compared to Earth's 9.81m/s2.