Answer:
the answer is well known as gravity
The given in this problem is that two balls are thrown at different times, different heights and velocities. A blue ball is thrown upward at a specific velocity at a lower altitude while a red ball is thrown downwards at a specific speed and at a higher height. In this case, we are asked here to describe the graph of the behavior of the balls as a function of time. The x-axis then is time while the y-axis is the velocity of the ball. The blue ball has a quadratic function while the red ball is more or less exponential. See the attached figure for reference.
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 