Answer:
It's helps Emily became when she swims her hair is not in the way creating friction and making her swim faster. friction acts between two metals blocks that slide past each other.
Explanation:
Answer:
Electromagnetic waves do not require a medium in order to transport their energy. Mechanical waves are waves that require a medium in order to transport their energy from one location to another. ... Sound is a mechanical wave and cannot travel through a vacuum.
Answer:
0 m/s²
Explanation:
The velocity is constant, so there is no acceleration.
Answer:
Decreased by a factor of 4.5
Explanation:
"We have Newton formula for attraction force between 2 objects with mass and a distance between them:

where
is the gravitational constant on Earth.
are the masses of the object and Earth itself. and R distance between, or the Earth radius.
So when R is tripled and mass is doubled, we have the following ratio of the new gravity over the old ones:




Since
and 

So gravity would have been decreased by a factor of 4.5