Answer:
A)
B) 
Explanation:
A) Using the Archimedes' force we can find the weight of water displaced:

Where:
: is the weight of the block in the air = 20.1 N
: is the weight of the block in the water = 15.3 N

Now, the mass of the water displaced is:

The volume of the block can be found using the mass of water displaced and the density of the water:

B) The density of the block can be found as follows:

I hope it helps you!
B) a rock being tossed high into the air
It's the energy your body spends to just keep you breathing and your heart beating ... just being alive, without trying to DO anything.