How does the length of a pendulum's string affect its swing time?

The relationship between the length of a pendulum's string and its swing time is a fundamental concept in physics. When the string of a pendulum is longer, the pendulum has a greater distance to travel during its swing. The length of the string directly influences the period of the swing, which is the time it takes for the pendulum to complete one full cycle from the starting position to the lowest point and back again.

In simple terms, a longer string allows the pendulum to swing slower because it experiences a longer arc and more gravitational pull over a greater distance, which takes more time to complete. This results in a longer period for the swing. Hence, as the length of the pendulum's string increases, the time it takes to complete one swing also increases, confirming that a longer string takes longer to complete one swing.

This principle is well-supported by the formula for the period of a simple pendulum, which shows that the period is proportional to the square root of the length of the string. Therefore, a longer string leads to a longer swing time, making this option the correct choice.