Answer:
Explanation:
To find the amplitude of the sound, we must first determine the wavelength and the phase difference between the two speakers.
For the wavelength;
Recall that, the separation between two successive max. and min. intensity points are 
Thus; for both speakers; the wavelength of the sound is:


λ = 80 cm
The relation between the path difference(Δx) and the phase difference(Δ∅) is:

where;
Δx = 10 cm
λ = 80 cm
Δ∅ = π rad
∴







Suppose both speakers are placed side-by-side, then the path difference between the two speakers is: Δx = 0 cm
Thus, we have:



∴
The amplitude of the sound wave if the two speakers are placed side-by-side is:



A = 0.765a
B. The number of coils of wire around the core
The average speed of an object is defined as the distance traveled divided by the time elapsed. Velocity is a vector quantity, and average velocity can be defined as the displacement divided by the time. According To a website on google
The correct answer is
Air resistance
In fact, when a ball is in free fall, there are two forces acting on it:
- its weight (force of gravity), acting downward
- the air resistance, acting upward
The effect of the weight is to accelerate the ball, because its direction is the same as the direction of motion of the ball, while the effect of the air resistance is to slow down the ball, because its direction is opposite to that of the motion.