Answer:
4939200 m
Explanation:
v = Velocity of sound in air = 343 m/s (general value)
For the echo to reach Rip van Winkle it must cover the distance to the mountain twice. So, time taken for the sound traveling to the mountain once

Distance is given by

The distance to the mountain is 4939200 m
<span>
The length of daylight on the moon is about 29.5 days.</span>
From the earliest days, the Moon has been there in the Solar
System and there has never been a period when we couldn't gaze upward in the
night sky and either observe the Moon hanging there, or realize that it would
be back the precise one night from now (i.e. a New Moon).
A day on the Moon keeps going as long as 29.5 Earth days. We
can say that it would take 29.5 days for the Sun to move the distance over the
sky and come back to its unique position once more.
Explanation:
Methane (CH4) is 30 times stronger than carbon dioxide as an absorber of infrared radiation.
Answer: Three forces act significantly on a freely floating helium-
filled balloon: gravity, air resistance (or drag force), and a
buoyant force.
Explanation:
The air pressure on the bottom of the balloon is slightly higher than the air pressure on the top of the balloon (because of the altitude difference). This difference gives rise to the bouyant force. This force competes with gravity as the two main forces acting on the balloon. Every time your feet hit the ground when you are running, the ground hits your feet with an equal and opposite force. Newton’s third law explains how balloons and rocket engines work. When the neck of an inflated balloon is released, the stretched rubber material pushes against the air in the balloon. The air rushes out of the neck of the balloon.