# Homework Help: Period of a pendulum is measured to be 3.00 s

1. Oct 29, 2011

### Fabio010

1. The problem statement, all variables and given/known data

The period of a pendulum is measured to be 3.00 s in the reference frame of the pendulum.

2. Relevant equations
What is the period when
measured by an observer moving at a speed of 0.960c relative to the pendulum?

3. The attempt at a solution

I dont want to change the referencial frames. So:

Δt = 3.00 s

Δt = $\frac{Δto}{\sqrt{1-0.9216}}$
Δto = 0.84s

So, the period of pendulum measured by the observer (with speed 0.960c) is 0.84 s ?

right?

The solution, they changed the frames. So pendulum moves with 0.960c.

Δto = 3,00s and Δt= 10.00s.

Is my solution correct, or i need to change the frames?