Answer:

Explanation:
= Change in frequency = 2.1 Hz
= Frequency of source of sound = 440 Hz
= Maximum of the microphone
= Speed of sound = 343 m/s
= Time period = 2 s
We have the relation

Amplitude is given by

The amplitude of the simple harmonic motion is
.
Answer:
W=1055N
Explanation:
In order to solve this problem, we must first do a drawing of the situation so we can visualize theh problem better. (See attached picture)
In this problem, we will ignore the board's weight. As we can see in the free body diagram of the board, there are only three forces acting on the system and we can say the system is in vertical equilibrium, so from this we can say that:

so we can do the sum now:

when solving for the Weight W, we get:

and now we can substitute the given data, so we get:
W=410N+645N
W=1055N
Answer:
law of Action and Reaction F = 2250 N
Explanation:
The tractor and the trailer are two bodies that interact, therefore, by the law of Action and Reaction, the force that one applies on the other is equal to the force that the second body (trailer) applies on the first (tractor), but with opposite direction
F = 2250 N
directed from trailer to tractor
If everything else is held constant ... the substance from which
the conductor is formed, its cross-sectional area, its temperature
everywhere along its length ... then yes, its resistance will be
directly proportional to its length.