It is known that the air density is 1.29Kg per M & sup3;, and the buoyancy of a junior high school student in the air is about several n?

It is known that the air density is 1.29Kg per M & sup3;, and the buoyancy of a junior high school student in the air is about several n?

Suppose the weight of the junior high school student is 50kg, because the water content in the human body is very high, so the density is approximately 1000kg / m3, then the volume of the student is 0.05m3, then the air is removed so much, then the buoyancy is 0.05 * 1.29 * 10N / kg = 0.645n, so it is about 0.6N to 0.7n

If the known air density is 1.29 kg / m3, then the buoyancy of the balloon is 0

1290

The mass of air in your test room is about () (the known density of air is 1.29kg/m3)
A. Tens of grams B. thousands of grams C. hundreds of kilograms D. tens of milligrams

The air mass in the examination room M = ρ v = 1.29kg/m3 × 120m3 = 154.8kg