Posted by **Sam** on Thursday, December 1, 2011 at 10:35pm.

1.Two balls, each with a mass of 0.871 kg,

exert a gravitational force of 8.23 × 10−11 N

on each other.

How far apart are the balls? The value

of the universal gravitational constant is

6.673 × 10−11 Nm2/kg2.

Answer in units of m

I got .785 which is correct.

002 10.0 points

Mars has a mass of about 6.56 × 1023 kg,

and its moon Phobos has a mass of about

9.2 × 1015 kg.

If the magnitude of the gravitational force

between the two bodies is 4.68 × 1015 N,

how far apart are Mars and Phobos? The

value of the universal gravitational constant

is 6.673 × 10−11 N · m2/kg2.

Answer in units of m

Don't get this.