Why do you have to say "please" and "thank you"?​

We have to say ''please'' and ''thank you'' because we are requesting another person then speak please, and anyone help u then we are saying thank you.

It is also a good behaviour or manner of human being.

Thanks♥♥

answer:

heartless

explanation:

answer:

because the gravitational attraction of our sun for the earth is the centripetal force causing the earth's circular motion around the sun, we can use netwon's law of universal gravitation to find the mass of the sun without ever actually visiting the sun. this is the same technique you would use to determine the mass of cygnus x-1 with a probe. the earth, orbiting the sun, plays the same role as the probe sent to orbit cygnus x-1.

f(force of gravity) = f(centripetal force)

explanation: