The Average density of Earth is 5.52g/cm^3. What is its density in a. kg/m^3 b. lb/ft^3. Please help me set up these equations. Thank you!

Answer 1

5.52 g/cc.
You want to multiply the 5.52 g/cc by factors so that g is changed to kg and cc (cubic cm) is changed to m^3. I'm sure you have heard of dimensional analysis.
We can change one unit at a time.
1000 g = 1 kg
5.52 g x (1 kg/1000g) = 0.00552 kg/cc.

There are 100 cm to 1 m
0.00552 kg/cubic cm x (100 cm/m)(100 cm/m)(100 cm/m) = 5520 kg/m^3.

That's how you do it. I'll let you do the one on lbs/ft^3.
By the way, you can always check your answer by typing the problem into google. For example, for the above type into the google window the following without the quotation marks.
"5.52 g/cc to kg/m^3" and hit the enter button. 5520 kg/m^3 will be returned as the answer.