## Physics: Principles with Applications (7th Edition)

You would not measure any changes in your own heartbeat, mass, height, or waistline. The situation described is essentially an inertial reference frame. The laws of physics are the same in all inertial reference frames, so inside the ship, everything is exactly the same as it would be on Earth (minus the gravity). However, to observers on Earth, you are in a reference frame moving away at 0.6c. The value of $\gamma$ is $\frac{1}{\sqrt{1-v^{2}/c^{2}}}=1.25$. Assume you are facing in the direction of motion. To Earth observers, your heartbeat appears slowed by a factor of $\gamma = 1.25$, your mass has increased by a factor of $\gamma = 1.25$, and your front-to-back distance has decreased by a factor of $\gamma = 1.25$, affecting your waistline. Your height is unchanged.