Answer:
The Forces of Flight
At any given time, there are four forces acting upon an aircraft.
These forces are lift, weight (or gravity), drag and thrust. Lift is
the key aerodynamic force that keeps objects in the air. It is the
force that opposes weight; thus, lift helps to keep an aircraft in
the air. Weight is the force that works vertically by pulling all
objects, including aircraft, toward the center of the Earth. In order
to fly an aircraft, something (lift) needs to press it in the opposite
direction of gravity. The weight of an object controls how strong
the pressure (lift) will need to be. Lift is that pressure. Drag is a
mechanical force generated by the interaction and contract of a
solid body, such as an airplane, with a fluid (liquid or gas). Finally,
the thrust is the force that is generated by the engines of an
aircraft in order for the aircraft to move forward.
Explanation:
Answer:
Number of revolutions=1.532 revolutions
Explanation:
Given data
Distance s=8.0 m
Angular speed a=1.2 rev/s
To find
Number of revolutions
Solution
From the equation of simple motion we not that

So for the number of revolutions she makes is given as

Answer:
a) The shear stress is 0.012
b) The shear stress is 0.0082
c) The total friction drag is 0.329 lbf
Explanation:
Given by the problem:
Length y plate = 2 ft
Width y plate = 10 ft
p = density = 1.938 slug/ft³
v = kinematic viscosity = 1.217x10⁻⁵ft²/s
Absolute viscosity = 2.359x10⁻⁵lbfs/ft²
a) The Reynold number is equal to:

The boundary layer thickness is equal to:
ft
The shear stress is equal to:

b) If the railing edge is 2 ft, the Reynold number is:

The boundary layer is equal to:

The sear stress is equal to:

c) The drag coefficient is equal to:

The friction drag is equal to:

Answer:
Same frequency, shorter wavelength
Explanation:
The speed of a wave is given by


where,
f = Frequency
= Wavelength
It can be seen that the wavelength is directly proportional to the velocity.
Here the frequency of the sound does not change.
But the velocity of the sound in air is slower.
Hence, the frequency remains same and the wavelength shortens.