Alternating current (AC) flows half the time in one direction and half the time in the other, changing its polarity 120 times per second with 60-hertz current.
Your answer is 3 ( 1 calcium atom and 2 bromine atoms)
Answer:
the outer covering of a bird is usually for camoflauge (idk how to spell) or to attract mates and the outer part of a tree is used for protection i think, correct me if im wrong ;-;
Explanation:
The acceleration of the runner in the given time is 2.06m/s².
Given the data in the question;
Since the runner begins from rest,
- Initial velocity;

- Final velocity;

- Time elapsed;

Acceleration of the runner; 
<h3>Velocity and Acceleration</h3>
Velocity is the speed at which an object moves in a particular direction.
Acceleration is simply the rate of change of the velocity of a particle or object with respect to time. Now, we can see the relationship from the First Equation of Motion

Where v is final velocity, u is initial velocity, a is acceleration and t is time elapsed.
To determine the acceleration of the runner, we substitute our given values into the equation above.

Therefore, the acceleration of the runner in the given time is 2.06m/s².
Learn more about Equations of Motion: brainly.com/question/18486505