Mechanical or Electromagnetic
Answer:
Recoil speed,
Explanation:
Given that,
Mass of the comet fragment, 
Speed of the comet fragment, 
Mass of Callisto, 
The collision is completely inelastic. Assuming for this calculation that Callisto's initial momentum is zero. So,

V is recoil speed of Callisto immediately after the collision.

So, the recoil speed of Callisto immediately after the collision is 
Answer:
All these statement are true
Explanation:
Gravity will be acting like a centripetal force for the circular motion of object around earth, which makes it perpendicular to the velocity vector. In the case of elliptical motion, gravity can still be divided into 2 vectors, one parallel and the other perpendicular to the velocity. At the nearest point in elliptical motion, gravity is directly perpendicular to velocity just like in circular motion. At the farthest point, the potential energy is minimized and has been converted into kinetic energy. Therefore at this point the speed is greatest.
It would take 3.6 hours for a car to travel 200 km going 55 km/hr.