Answer:
C.) The amount of mass used up in holding a nucleus together.
Explanation:
The mass defect of a nucleus represents the mass of the energy binding the nucleus. It is the difference between the mass of the nucleus and the sum of the masses of the nucleons of which it is composed.
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Explanation :
The forces acting on hot- air balloon are:
Weight, (W)
Force due to air resistance, (F)
Upthrust force, (U)
Its weight W is acting in downward direction. The upthrust force U acts in upward direction. When the balloon is moving upward, the air resistance is in downward and vice versa.
In this case, the hot-air balloon descends vertically at constant speed.
so, 
and 
so,
....................(1)
when it is ascending let the weight that it is releasing is R, so
..........(2)
solving equation (1) and (2)

2F is the weight of material that must be released from the balloon so that it ascends vertically at the same constant speed.
Answer:
no, when a plastic rod is rubbed with a duster, electrons are transferred from one material to the other. The material that gains electrons becomes negatively charged. The material that loses electrons becomes positively charged.
Explanation:
Answer:
A hypothesis is what you think will happen.
A conclusion is the results of an experiment summarized.
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Answer:I need the ans to this one too
Explanation: