The number of protons and neutrons combined in an atom is called the mass number.
Reactions happen instantly even if some are slower than others they all happen instantly so the answer would be A.
Answer:
the first one I believe is right but I could be wrong.
Answer:
v = 1.5 m/s
Explanation:
Given that,
Distance covered by a person, d = 105 m
Time taken, t = 70 s
We need to find the average speed of the person. We know that the average speed is given by :

So, the average speed of the person is equal to 1.5 m/s.