Here is my problem that I have partly solved. An astronaut visits planet x. She takes out a 50 cm pendulum and records a period of oscillation of 2 seconds. Then the astronaut visits planet y, takes out the same pendulum and records a period of oscillation of 1.5 seconds. Which planet has the largest gravity? What is the value of gravity on that planet? g = 4pi^2(50)/2^2 = 493.4802201 for planet x g = 4pi^2(50)/1.5^2 = 877.298169 for planet y planet y has the largest gravity Now I'm not sure how to find the value of gravity for planet y.