Saw the 5m long steel bar into small sections of the same length for 6 times, how long is each section? For example, saw each section for 2 minutes, saw 6 sections for several minutes?

Saw the 5m long steel bar into small sections of the same length for 6 times, how long is each section? For example, saw each section for 2 minutes, saw 6 sections for several minutes?

Saw 6 times, the number of segments is
6 + 1 = 7 (section)
Length of each segment
5 △ 7 = 5 / 7 (m)
Saw 6 sections, need to saw
6-1 = 5 (Times)
need
2 × 5 = 10 (min)

The buoyancy of a hydrogen balloon in the air () gravity

Greater than or equal to
Buoyancy is greater than gravity
As the balloon rises, the buoyancy decreases, the buoyancy does not rise and eventually equals gravity

When a hydrogen balloon rises at a constant speed, it is subjected to buoyancy F, gravity g and air resistance F. the relationship between these forces is ()
A. F＞G+fB. F=G+fC. F＞G-fD. F=G-f

When the hydrogen balloon rises at a constant speed, it is affected by the balance force; in the vertical direction, the upward force is the buoyancy force F of the air; the downward force is the gravity g and the air resistance f; so the upward force is equal to the downward force, that is, f = G + F; so B is correct; ACD is wrong; so B is selected