Final answer:
The period of the pendulum, which completes 91 cycles in 131 seconds, is approximately 1.44 seconds per cycle.
Step-by-step explanation:
The period of a pendulum is the time it takes for one complete cycle of movement, which includes swinging in one direction and then back to the starting point. To calculate the period (T), we need to divide the total time by the number of cycles. Given that the space explorer on the unfamiliar planet observed the pendulum completing 91.0 full swing cycles in 131 seconds, we use the following calculation:
Period (T) = Total time / Number of cycles = 131 s / 91.0 cycles
Upon performing the division, we find that the period of the pendulum is approximately 1.44 seconds per cycle.