Answer:
Feathers are great thermal insulators.
Explanation:
Feathers are great thermal insulators. The loose structure of down feathers traps air.
As a result, energy cannot be transmitted easily through down feathers. This means birds are insulated from cold air outside, plus their body heat doesn't escape easily either.
Human beings discovered that down feathers are good for insulation long ago. For example, documents from the 1600s show that Russian merchants sold “bird down" to the Dutch hundreds of years ago.
Today, down is used in all sorts of products, including coats, bedding, and sleeping bags, to help better insulate the user from cold weather. Down can be collected from many different types of birds, but most of today's supply comes from domestic geese.
If you have a down coat or comforter, is it all down? In the United States, laws require that products labeled “100 percent down" contain only down feathers.
If your product is labeled “down," it can contain a mixture of both down feathers and synthetic fibers. Not all down feathers are created equal, though.
Down insulation is rated on a measure called “fill power." The higher the fill power, the more the down insulates.
The highest fill-power rating — 1200 — goes to eiderdown, which comes from the Common Eider duck. Eiderdown tends to be expensive.
sir what's the question you have all you wrote is it's not b
Explanation:
When you run, your body has a kinetic energy and when you fall while running, the friction between the carpet and your foot, transforms the kinetic energy into thermal energy or heat energy. This can even cause, real burn if the skin were too hot.
Answer:
A. It must be zero
Explanation:
A spacecraft leaves the solar system at a velocity of 1,500 m/s. The net force on this spacecraft is zero. What can we say about the spacecraft's acceleration?
According to Newton's second law
Force = Mass × acceleration
If the net force is zero
0 = mass × acceleration
0 = ma
a = 0/m
a = 0m/s²
this shows that the acceleration will be zero If the net force is zero
