I’m assuming that’s m^3? If so then simply divide 160,000 by 20 and you get the answer.
8,000 kg/m^3
Group is a collection of people that are in the same place and share some characteristics. examples are a group of students, a group of engineers and etc. while aggregate is a collection of people that are in the same place but do not share anything in common
Answer: Average acceleration is -2.407 
Explanation:
Average acceleration is equal to change in velocity divided by time taken
therefore, 
=> 
The object is in free fall when and only when it is being affected by gravity alone. It is not being influenced by a significant amount of air resistance will always be in free fall. F(net)/m = acceleration
They are inversely proportional to each other