Answer: D. Infrared
Infrared is the best way to observe it.
If you stand up in a big room and echo, your voice will echo
from the walls. As long as the room is empty. Since
the speed of sound is constant, depending on air density, the more humid the
air the faster and farther sound travels. The
speed of sound is constant, you could measure the time it takes for your voice
to echo off the walls. The same thing happens with Doppler radar, but it’s not voice,
it has higher frequency signals.<span> </span>
It would last as long as the applied force continued, or until the accelerating object hit something.
The distance in meters she would have moved before she begins to slow down is 11.25 m
<h3>
LINEAR MOTION</h3>
A straight line movement is known as linear motion
Given that Ann is driving down a street at 15 m/s. Suddenly a child runs into the street. It takes Ann 0.75 seconds to react and apply the brakes.
To know how many meters will she have moved before she begins to slow down, we need to first list all the given parameters.
From definition of speed,
speed = distance / time
Make distance the subject of the formula
distance = speed x time
distance = 15 x 0.75
distance = 11.25m
Therefore, the distance in meters she would have moved before she begins to slow down is 11.25 m
Learn more about Linear motion here: brainly.com/question/13665920
