The railroad crossing lights turn red, so mckayla and her sister must stop and wait for the train to pass by. as they wait, mckayla's sister kylie grabs her phone and uses an app to measure the frequency of the approaching train's horn. the app reads 429 hz. assuming the train's original horn frequency is 400 hz and the speed of sound is 330 m/s, how fast is the train going in m/s and miles per hour

The speed of the approaching train is 23.93 m/s or 53.54 mph.

The speed of the approaching train can be determined using Doppler effect formula as shown below;

1 mile = 1609 meters

Learn more about Doppler effect here: link

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.