An airplane wing is designed to make the air move <em>faster over the top than under the bottom. (c)</em> They do this by making the top of the wing curved and the bottom flat, so the air that flows over the top has farther to go.
It turns out, according to a scientist named Bernoulli, that air exerts lower pressure when it moves faster. So if it moves faster over the top of the wing, then there's less pressure on the top of the wing and more on the bottom, and the wing thinks there's a force that's LIFTING it . . . <em>very convenient and useful</em> if the wing is part of an airplane !
Answer:
481 m
Explanation:
To fall 235 m, the time required is
t = √(2H/g)
t= √(2
235/9.8)
t=6.92 seconds.
The supplies will travel forward
6.92 69.4 ≈ 481 m
Therefore, the goods must be dropped 481 m in advance of the recipients.
If swimmers had a choice of the water slides shown in this figure,
they would all go home dry, since there is no figure. I'll have to try to
answer this question based on only the words in the text, augmented
only by my training, education, life experience, and human logic.
-- Both slides are frictionless. So no energy is lost as a swimsuit
scrapes along the track, and the swimmer's kinetic energy at the
bottom is equal to the potential energy he had at the top.
-- Both slides start from the same height. So the same swimmer
has the same potential energy at the top of either one, and therefore
the same kinetic energy at the bottom of either one.
-- So the difference in the speeds of two different swimmers
on the slides depends only on the difference in the swimmers'
mass, and is not influenced by the shape or length of the slides
(as long as the slides remain frictionless).
If both swimmers have the same mass, then v₁ = v₂ .
