1. At the top of a roller coaster loop-the-loop, the car and rider are upside down. If the radius of the loop is 13.2 m, with what minimum speed must the car traverse the loop so that the rider does not fall out while upside down at the top?

2. A rotating cylinder about 17 km long and 8.4 km in diameter is designed to be used as a Space Colony. Its rotations imitate the gravitational acceleration due to gravity as experienced on the Earth's surface. What is the tangential velocity of the sensor attached to the external wall of the cylinder? Round the answer to the nearest integer.