Answer:

Explanation:
If we have a periodic wave we need to satisfy the following basic relationship:

From the last formula we see that the velocity is proportional fo the frequency.
For this case we have the following info given by the problem:

We know that the frequency is the reciprocal of the period so we have this formula:

And if we replace we got:

Now since we have the value for the wavelength we can find the velocity like this:

And if we convert this into cm/s we got:

The number of protons in an atom is represented by the atomic number.
hope this helps
Answer:
The vector sum of all forces acting on it is zero, its at equilibrium.
Explanation:
The bag of marbles hanging on a spring scale applies its weight downwards, which was counterbalanced by the reaction from the spring scale (obeying the Newton's third law of motion). And since no external forces are applied to the system, thus the equilibrium of the system.
If the weight of the bag is greater than the reaction from the spring scale, the scale breaks and the system would not be balanced.
Answer:
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Explanation:UGGGGGGGGGIBKLJ
Answer:
d. )directed upward.
Explanation:
As the electron has a negative charge, when under the influence of an electric field, is subject to an electric force, which direction is the opposite to the direction of the electric field.
This is because the electric field has the same direction that the force on a positive test charge at the same point.
As the electric field points vertically downward, the electric force on the electron (a negative charge) points vertically upward.
So, the statement d. is the one that results to be true.