A subgroup of a group can also be defined as another abstract group along with an injective homomorphism (or embedding) from that abstract group to the given group. Here, the other abstract group can be naturally identified via its image under the homomorphism, which is the subgroup in a more literal sense.
For the skate brand of the same name, see Roller Derby (brand). Roller derby is a contact sport played by two teams of five members roller skating in the same direction around a track. Game play consists of a series of short match ups (jams) in which both teams designate a jammer who scores points by lapping members of the opposing team.
1Kingda Ka: the world's tallest and fastest roller coaster. Arms down, head back and hold on. With only 28 seconds, the Kingda Ka may not be very long, but it's bound to leave you wide eyed and twitching. Located at Six Flags Great Adventure in New Jersey, USA, it's the tallest and fastest roller coaster in the world. The train is launched by a hydraulic launch mechanism to 128 miles per hour (206 km/h) in 3.5 seconds.