Answer:
Ferromagnetism, physical phenomenon in which certain electrically uncharged materials strongly attract others. Two materials found in nature, lodestone (or magnetite, an oxide of iron, Fe3O4) and iron, have the ability to acquire such attractive powers, and they are often called natural ferromagnets.
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Answer:
the relative speed should be 40mph
Explanation:
Answer: reliable
Explanation:
Reliable (marketing research) information is collected from questions (measurements) that are free from systematic or statistical error. An absence of systematic error implies that the respondents (i.e., the sampled people) who answer questions actually understand what the questions were asking.
The gravitational force between two objects is given by:
where
G is the gravitational constant
m1 and m2 are the masses of the two objects
r is the separation between the two objects
The distance of the telescope from the Earth's center is
, the gravitational force is
and the mass of the Earth is
, therefore we can rearrange the previous equation to find m2, the mass of the telescope: