Answer: amplitude
Explanation: This describes the maximum amount of the displacement of a particle from it rest position. Usually, it is measured in metres
Since we are considering AM which is amplitude modulation, a technique used in electronic communication, most commonly for broadcasting information through a radio carrier wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is diversified in proportion to that of the message signal being broadcasted.
Answer:

Explanation:
given,
s = 400- 16 t²
we know,
Velocity of an object is defined as the change in displacement per unit change in time.
velocity an also be return as




Hence, instantaneous velocity function given by 
To calculate instantaneous velocity, you need to insert value of time.
ex, instantaneous velocity at t = 4 s
v = -32 x 4 = -128 m/s.
The most common unit is meters (m for short). It is the base unit for distance or displacement in the metric system. If you are dealing with larger distances, you might use kilometers (I'm for short) which is just 1000 meters. On the other hand, centimeter (cm) are used for small distances and are 1/100 of a meter. Another common unit is millimeters (mm) which is 1/1000 of a meter.