High precision and good validity <span />
Answer: 2.9 m/s
Explanation:
The frequency of the beat is 4 Hz
The relative Doppler frequency is 235 + 4 = 239 Hz
We would be solving this question, using the formula for Doppler's effect
f(d) = f(v+vr)/(v-vs), where
F = 235 Hz
F(d) = 239 Hz
v = 344 m/s and vr = vs
239 = 235 (344 + vr) / (344 - vr)
239 ( 344 - vr) = 235 (344 + vr)
82216 - 239 vr = 80849 + 235 vr
82216 - 80849 = 235 vr + 239 vr
1376 = 474 vr
vr = 1376/474
vr = 2.9 m/s
Thus the speed the platform should move is 2.9 m/s
There are known as B. meteorites: asteroids are much larger.
The number of nuclei that have decayed after three half-lives is 12.5% of the original mass.
<h3>
What is half live of radioactive isotope?</h3>
The half life of a radioactive isotope is the time taken for the element to decay to half of its original mass.
<h3>Number of nuclei decayed after 3 half lives</h3>
N = N₀/(2³)
N = N₀/8
N = 0.125N₀
N = 12.5% of N₀
where;
- N is n number of nuclei that have decayed after 3 half lives
- N₀ is the original mass
Thus, the number of nuclei that have decayed after three half-lives is 12.5% of the original mass.
Learn more about half life here: brainly.com/question/10525285
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