Using the principle of floatation.
u = w............(a)
Upthrust of fluid is equal to the weight of the object.
Let the volume of the wood be V.
The upthrust u, is related to the volume submerged in water, and that is 1/5 of it volume, that is (1/5)V = 0.2V
Formula for upthrust, u = vdg
where v = volume of fluid displaced
d = density of fluid
g = acceleration due to gravity
weight, w = mg
where m = mass
g = acceleration due to gravity
From (a)
u = w
vdg = mg Cancel out g
vd = m
The v is equal to 0.2V, which is the submerged volume. Notice that the small letter v is volume of fluid displaced, and capital V is the volume of the solid.
d is density of fluid which is water in this case, 1000 kg/m³
0.2V * 1000 = m
200V = m
Hence the mass of the object is 200V kg.
But Density of solid = Mass of solid / Volume of solid
= 200V / V
= 200 kg/m³
Density of solid = 200 kg/m³
Atomic mass= number of protons + number of neutrons

hope this helps
We know that:
d=vt
d=32mph*5h
d=160mi
The process of refraction of light occurs when light rays bends when travelling between media of different densities.
What is refraction of light?
Refraction of light is the bending of light rays or the change in the direction of light rays as it travels between media of different densities.
Light waves travel faster in media of less density than media of more density.
The change in density of the media makes light waves to be bend towards or away from the normal.
For example, when light travels from less dense air to more dense water, the light rays are bent towards the normal. However, when light rays travel from water to air, the light rays are refracted away from the normal.
In conclusion, refraction of light waves occur when light crosses the boundary of media of different densities.
Learn more about refraction of light at: brainly.com/question/27932095
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30 Grams would be your answer (I took the test and got it right)