What force is needed to press the block to immerse it totally if the mass of the silver block is 1.5 kg?

To answer this question, we need to use the principle of buoyancy, which states that the buoyant force (or the force needed to totally immerse an object in a fluid) is equal to the weight of the fluid displaced by the object.

For a block of silver, the volume can be calculated using the formula:

Volume = Mass / Density

The density of silver is approximately 10,490 kg/m^3. So, the volume of the silver block is:

Volume = 1.5 kg / 10,490 kg/m^3 = 0.000143 m^3

The fluid here is assumed to be water, and the density of water is approximately 1000 kg/m^3. The weight of the water displaced by the silver block can be calculated using the formula:

Weight = Volume x Density x Gravity

Substituting the known values, we get:

Weight = 0.000143 m^3 x 1000 kg/m^3 x 9.8 m/s^2 = 1.4 N

Therefore, the force needed to totally immerse the block of silver in water is approximately 1.4 Newtons.