Answer:

Explanation:
given,
frequency of tuba.f = 64 Hz
Speed of train approaching, v = 8.50 m/s
beat frequency = ?
using Doppler's effect formula

v_s is the velocity of the source
v is the speed of sound, v = 340 m/s
now,

f' = 65.64 Hz
now, beat frequency is equal to



hence, beat frequency is equal to 1.64 Hz
One should check the battery every week.
A battery if not maintained properly can cause it to die earlier or get damaged. The reasons why should the battery be checked regularly is that due to improper management of the battery and also the weather conditions, the battery usually gets corroded easily and the battery won't be able to work properly.
The connections must be checked properly so that the battery gets charged properly and should not die while driving.
Electricity and magnetism can be considered as part of the same phenomenon because both are generated by electromagnetic forces.
<h3>What is electricity?</h3>
Electricity is the movement or flow of negatively charged electrons through a suitable conductor where a charge is applied.
Moreover, magnetism is a natural phenomenon caused by the generation/movement of electric charges.
In conclusion, electricity and magnetism can be considered as part of the same phenomenon because both are generated by electromagnetic forces.
Learn more on electricity and magnetism here:
brainly.com/question/25144822
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C. <span>People need time to shift between two different stimuli.</span>