Answer:
8. 2.75·10^-4 s^-1
9. No, too much of the carbon-14 would have decayed for radiation to be detected.
Explanation:
8. The half-life of 42 minutes is 2520 seconds, so you have ...
1/2 = e^(-λt) = e^(-(2520 s)λ)
ln(1/2) = -(2520 s)λ
-ln(1/2)/(2520 s) = λ ≈ 2.75×10^-4 s^-1
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9. Reference material on carbon-14 dating suggests the method is not useful for time periods greater than about 50,000 years. The half-life of C-14 is about 5730 years, so at 65 million years, about ...
6.5·10^7/5.73·10^3 ≈ 11344
half-lives will have passed. Whatever carbon 14 may have existed at the time will have decayed completely to nothing after that many half-lives.
By definition, the gain in PE (potential energy) is
ΔPE = m*g*h
Given:
mg = 40 N (Note that m*g = weight)
h = 5 m
ΔPE = (40 N)*(5 m) =200 J
Answer: 200 J
Explanation:
According to Dalton's atomic theory, all the atoms are individual, all the atoms of the same element are identical in properties and mass, the compound is formed from two or more kinds of the atoms, all the matter is made up of small atoms and the chemical reaction is a rearrangement of the atoms.
The discoveries which contradicts the components of Dalton's atomic theory from the given discoveries are:
Nuclear reactions can change an atom of one element into an atom of another element.
Atoms of a given element can have different numbers of neutrons.
Atoms contain smaller particles: protons, neutrons, and electrons.
Answer:
Components: 0.0057, -0.0068. Magnitude: 0.0089 m/s
Explanation:
The displacement in the x-direction is:
While the displacement in the y-direction is:
The time taken is t = 304 s.
So the components of the average velocity are:
And the magnitude of the average velocity is
