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!
Velocity =displacement
Change in time
D=72km/hr
Time=20s
But the S.I unit of velocity is m/s so you woul have to change 72km/hr to m/s
Changing 72km to m
1 kilometer=1000meters
Then, 72 kilometers =?
72•1000/1
=72000m
Changing 72hours to seconds
If 1 hour = 3600 seconds
Then 72 hours=?
72•3600/1
=259200 seconds
Velocity =displacement
Change in time
V= 72,000
259,2005
=0.028m/s
The answer to your question is Speed
Ice is only thing which is mightier than steel because it can breaks things which are made up of steels like ships but in the sunlight ice melts away it means it cowards away.