4) Was kaufen sie? Several relatives of the Heinemann family are going shopping since they will be exchanging presents at Christmas time. Write the correct form of kaufen and the indefinite article for each sentence. Beispiel: Hanne / Buch 1. Herr und Frau Heinemann / Gitarre Hanne kauft ein Buch. 10

Hanne kauft ein Buch

Herr und Frau Heinemann kaufen eine Gitarre

Explanation:

because:

ich(I) kaufe

du (you) kaufst

er/ sie/es(he/she/it) kauft

wir(we) kaufen

ihr(you) kauft

sie(they) kaufen

Hanne is he/she/it

and

Herr und Frau Heinemann are sie(they)

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: