A solid block is attached to a spring scale. When the block is suspended in air, the scale reads 20.1 N; when it is completely immersed in water, the scale reads 15.3 N. A) What is the volume of the block?
B) What is the density of the block?

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!            

we need to know the time interval during which the force acts. impulse of force = momentum change