The main reason as to why those telescopes that are located above the Earth's atmosphere is because the atmosphere absorbs infrared light which comes from the sun and this affects the viewing done by the astronomers. That is why, this is considered as a great disadvantage for those ground-based telescopes. The answer would be the last option.
Answer:
Explanation:
We shall apply Doppler's effect to solve the problem .
Formula for apparent frequency for a source of sound approaching an observer is as follows .
f₁ = f₀ V / (V - v )
where f₁ and f₀ are apparent and real frequency of source , V and v is velocity of sound and velocity of approaching source respectively .
Putting the given values and knowing that speed of sound is 340 m /s
f₁ =346x 340 / (340 - 39.6 )
f₁ = 391.6 Hz
In case of receding train , the formula is
f₂ = f₀ V / (V + v )
Putting the values
f₂ = 346x 340 / (340 + 39.6 )
= 309.9 Hz
Change in frequency = 391.6 - 309.9
= 81.7 Hz .
Explanation:
Carbon-14 is normally used to date living organisms (all living things we know today contain mostly carbon). It can be used for samples up to about 60000 years old. Carbon-12 is the non-radioactive form that we encounter daily. Relative dating determines dates relative to each other, such as ordering of period or events.
Uranium 235 dating can determine date samples a million years old and up, so is more suited for rocks.
Answer:
Speed BA = 18 km/hr.
Explanation:
Given the following data;
Speed AB = 30km/hr
Speed BA = x km/hr
Average speed = 24 km/hr
To find the value of x;
Average speed = (Speed AB + Speed BA)/2
Substituting into the equation, we have
24 = (30 + x)/2
48 = 30 + x
x = 48 - 30
x = 18 km/hr
Answer and Explanation
Arranging the measured values in increasing order;
4.3s, 4.6s, 4.6s, 4.8s, 5.1s, 5.8s
The two outliers are obviously 4.3s and 5.8s; An outlier is a value in a statistical sample which does not fit a pattern that describes most other data point. Outliers make the average value complicated. So, it is usually better for data to be precise with data points spreading out around a small area.
So, the mean is the average of the four remaining data points after removing the outliers.
Mean = (4.6 + 4.6 + 4.8 + 5.1)/4
Mean = 4.775s
So, the value recorded should be 4.775s, 4.78s or 4.8s depending on the number of decimal places allowed.
QED!
