There is no image!?...was there meant to be something attached?
Answer:
a moving object will keep moving if not stopped
the sun being at the center of the solar system
Explanation:
Galileo is known for being the first person make a telescope, there fore being the first person to see that the sun is in the center of the solar system. he also came up with the theory that if something is pushed, it would keep moving until stopped by another force. For example, say you drop your pencil, it keeps falling until it hits the ground. That is exactly what Galileo did in his Leaning Tower of Pisa experiment and found that theory to be true.
I think the answer to this is centripetal force.
I may not be correct.
According to momentum conservation
15*3 = 45kgm/s
and the velocity of 5 kg mass will be
45/5 = 9 m/s