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A: 2 concrete blocks 6cm apart will have the least gravitational attraction to each other.
I believe that this answer was helpful.
Answer:Zero
Explanation:
Given
mass of ball 
If the ball is thrown upward then at maximum point velocity of ball is zero because ball is no longer able to move upward
Momentum(P) of a particle is given by



Therefore at the highest point momentum is zero .
Answer:
Mass can never be negative. Everything has mass. Just like how they ask you to find area under the graph in maths. If the area is in the 3rd and 4th quadrant, when calculated, you would get negative answer.However, area can not be negative because it is a place/ location. It's exactly the same as mass.
The most dangerous frequencies of electromagnetic energy are X-rays, gamma rays, ultraviolet light and microwaves. X-rays, gamma rays and UV light can damage living tissues, and microwaves can cook them. Hope this helps! =^-^=