In the Navy you get to do all kinds of fun things, like watch fighter jets come in for a landing on the deck of an aircraft carrier or launch heavy stuff off that same deck.
U.S. Ford-class aircraft carriers are now going to be equipped with a railgun-catapult hybrid, which is an "electrically powered electromagnetic projectile launcher", which they'll use to launch aircraft from the deck of a carrier.
But in this case the Navy crew aboard the U.S.S. Gerald R. Ford were just showing off their sweet new EMALS (Electromagnetic Aircraft Launch System), demonstrating how easy it is for the EMALS to launch a 4 ton sled.
-Via io9