Anasa scientist studies a moon rock whose mass is 9.30 kg and finds that it has an apparent mass of 6.30 kg when submerged in water.

This means the buoyancy or upward force is 3kg. Mass - buoyancy = apparent mass so 9.3 kg - 3 kg = 6 kg

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion

Most of the land is used for housing/commercial uses