Answer:
Option E: longer P-S intervals and lower peak intensity.
Explanation:
It was Kiyoo Wadati (Japanese seismologist) who researched about shallow and deep earthquakes and it was based on his research Charles Richter developed his earthquake magnitude scale in 1935. Instead of relying upon arrival time of seismic waves at different location, he focused on time difference between arrival of primary waves and secondary waves (slower than primary waves). He discovered that during shallow earthquake interval was short near the epicenter and shaking was strongest that means higher peak intensity, whereas, when the earthquake was of deep focus the interval between P-S waves increases and hence will have lower intensity.
For this question we should apply
a = v^2 - u^2 by t
a = 69 - 0 by 4.5
a = 69 by 4.5
a = 15.33
a = 6.85 m/s^2
If the answer in option is near to answer then , you can mark it as correct.
.:. The acceleration is 6.9 m/s^2
Answer:
b) 472HZ, 408HZ
Explanation:
To find the frequencies perceived when the bus approaches and the train departs, you use the Doppler's effect formula for both cases:
fo: frequency of the source = 440Hz
vs: speed of sound = 343m/s
vo: speed of the observer = 0m/s (at rest)
v: sped of the train
f: frequency perceived when the train leaves us.
f': frequency when the train is getTing closer.
Thus, by doing f and f' the subjects of the formulas and replacing the values of v, vo, vs and fo you obtain:
hence, the frequencies for before and after tha train has past are
b) 472HZ, 408HZ