Calculating Acceleration on Planet X Using Pendulum Period Measurements

[blackbyron]

Homework Statement

A pendulum (on earth) has a length of l and a mass of M and a period 1.4s. The pendulum is taken to planet X where the period is measured to be 2.25s. What is the acceleration due to gravity on planet X?

Homework Equations

So, t1 = 1.4s and t2 = 2.25s

I solved each of them for length t = 2pi * sqrt(L/g)
L1: .487m
L2: 1.257m

The Attempt at a Solution

The problem is that the velocity, the mass isn't given in the problem, so I am stuck on how to solve for acceleration. I don't think using kinematics would work, but any help would be appreciated.

 

[olivermsun]

What is known? t1 and t2, and actually, g1 (being 'g' on earth).

Two equations, two unknowns (g2 and L), and you don't even strictly care what L is...