The atomic number tells you the number of protons in an atom. This value never changes because the number of protons in the nucleus always remains constant. The mass number tells you the number of protons and neutrons (or nucleons) together: protons + neutrons = mass number. Since the number of neutrons in the nucleus varies, you can have different amounts of neutrons in the same type of atom. These varied types are called isotopes.
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Answer:
P = 140000 [Pa]
Explanation:
To solve this problem we must remember that pressure is defined as the relationship between Force on the area of a body.
In this particular problem, we are given the force acting on the upper surface of the block, including the force exerted by the atmospheric pressure.
P = F/A
where:
P = pressure [Pa] (units of Pascals)
F = force = 3.5*10⁴ [N]
A = area = 0.25 [m²]
P = 3.5*10⁴/0.25
P = 140000 [Pa]
