Answer:
a charge Q is transferred from an initially uncharged
Explanation:
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Answer:
The sound intensity of train is 1000 times greater than that of the library.
Explanation:
We have expression for sound intensity level,

A train whistle has a sound intensity level of 70 dB
We have

A library has a sound intensity level of about 40 dB
We also have

Dividing both equations

The sound intensity of train is 1000 times greater than that of the library.
Answered using calculus.
Antidifferentiated the acceleration to get velocity. Added variable c as we do not know if there was an extra number there yet.
Knowing that when time is 0, the velocity is 20, we can substitute those numbers into the equation and find that c = 20.
Now we have full velocity equation: v = 1.5t + 20
Now we substitute 4 into t to find out the velocity after 4 seconds. This gives us the final answer of 26m/s