Answer:
The strength of gravity decreases.
An example of that would be if you were in space; you float around because there's no gravity.
Answer:Same magnitude
Explanation:
When ball is dropped from shoulder height h then velocity at the bottom is given by

if it makes elastic collision then it will acquire the same velocity and riser up to the same height
If m is the mass of ball then impulse imparted is given by


Thus impulse imparted by gravity and Floor will have same magnitude of impulse but direction will be opposite to each other.
I belive it could be 6.5 but I could be wrong
Answer:
V=2.8 ml
Explanation:
volume of the cube is it would be 20.3 - 17.5 ml so 2.8 ml.
A closed system is a system that is completely isolated from its environment. The physical universe, as we currently understand it, appears to be a closed system. An open system is a system that has flows of information, energy, and/or matter between the system and its environment, and which adapts to the exchange.
D makes the most sense, but you just have to put two and two together and go with your gut feeling, first cross out the answers that don't make sense (A didnt make sense) and go from there! I hope the little bit above me helped you answer or decide :) Good luck!