An astronaut whose mass is 80. kg carries an empty oxygen tank with a mass of 10. kg. the astronaut throws the tank away with a speed of 2.0 m/s. with what velocity does the astronaut start to move off into space?

Copper has free electrons per cubic meter. a 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 a of current. (a) how much time does it take for an electron to travel the length of the wire? (b) repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current. (c) generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?

The roller coaster from problem #1 then tops a second hill at 15.0 m/s, how high is the second hill? 91.5 m 79.2 m 80.0 m 68.5 m

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?