# Pendulum on different planets

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.

brayrbob said:
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.
you've already calculated the gravity "g" for both planets.

(note: to obtain g in mks units, recalulate values using pendulum length of 0.5 meters instead of 50 cm.)

So the gravity for the planets is the vaule of gravity?
planet y has the vaule of gravity of g= 877.29cm/s^2

brayrbob said:
So the gravity for the planets is the vaule of gravity?
planet y has the vaule of gravity of g= 877.29cm/s^2
yes (at the location of the pendulum)