A comic-strip superhero meets an asteroid in outer space and hurls it at 100 m/s. The asteroid is a thousand times more massive than the superhero is. In the strip, the superhero is seen at rest after the throw. Taking physics into account, what would be his recoil speed? What is this in miles per hour?

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.