Answer:
1. external force;not change
2. all of the above
Bonus!!!!!!
Can i have brainliest
Answer: a.troposphere
Explanation: Most of the mass (about 75-80%) of the atmosphere is in the troposphere. Almost all weather occurs within this layer. Air is warmest at the bottom of the troposphere near ground level. Higher up it gets colder. Air pressure and the density of the air are also less at high altitudes.
That's the answer: I've attached the pic
The velocity is 0 m/s, as when it reaches the top, the object has no velocity for a small period of time as it then switched to a negative velocity when coming down