DBZK Episode 7
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Battle with Ten-Times Gravity! Goku's Race Against the Clock! is the seventh overall episode in the Dragon Ball Z Kai series. The original Japanese title is "Jū-bai Jūryoku to Tatakae! Gokū yo Shugyō wa Kakekko da" (10倍重力と闘え!悟空よ修行はかけっこだ). The episode first aired on May 17th, 2009. It's original American air date was May 27, 2010.
After three weeks, Goku succeeds in catching Bubbles. He is then issued his second challenge, to hit Gregory, the flying grasshopper, with a large mallet. After two weeks of trying, Goku succeeds and fully masters the planet's gravity in the process. King Kai then proceeds to teach Goku his signature technique; the Kaio-ken. On Earth, Gohan's training with Piccolo comes to a close, while the rest of the Z Fighters finish their training with Kami and go their separate ways.
- Watch this episode at 4Kids TV