a) Time of flight: 22.6 s
To calculate the time it takes for the cargo to reach the ground, we just consider the vertical motion of the cargo.
The vertical position at time t is given by

where
h = 2.5 km = 2500 m is the initial height
is the initial vertical velocity of the cargo
g = 9.8 m/s^2 is the acceleration of gravity
The cargo reaches the ground when

So substituting it into the equation and solving for t, we find the time of flight of the cargo:

b) 7.5 km
The range travelled by the cargo can be calculated by considering its horizontal motion only. In fact, the horizontal motion is a uniform motion, with constant velocity equal to the initial velocity of the jet:

So the horizontal distance travelled is

And if we substitute the time of flight,
t = 22.6 s
We find the range of the cargo:

Answer:
1225 J
Explanation:
The Gravitational potential energy (PEG) gained by a mass lifted above the ground is given by

where
m is the mass
g = 9.8 m/s^2 is the acceleration due to gravity
h is the height at which the object has been lifted
In this problem, we have
m = 250 kg
h = 0.5 m
So, the PE of the object is

Answer:
Feathers are great thermal insulators.
Explanation:
Feathers are great thermal insulators. The loose structure of down feathers traps air.
As a result, energy cannot be transmitted easily through down feathers. This means birds are insulated from cold air outside, plus their body heat doesn't escape easily either.
Human beings discovered that down feathers are good for insulation long ago. For example, documents from the 1600s show that Russian merchants sold “bird down" to the Dutch hundreds of years ago.
Today, down is used in all sorts of products, including coats, bedding, and sleeping bags, to help better insulate the user from cold weather. Down can be collected from many different types of birds, but most of today's supply comes from domestic geese.
If you have a down coat or comforter, is it all down? In the United States, laws require that products labeled “100 percent down" contain only down feathers.
If your product is labeled “down," it can contain a mixture of both down feathers and synthetic fibers. Not all down feathers are created equal, though.
Down insulation is rated on a measure called “fill power." The higher the fill power, the more the down insulates.
The highest fill-power rating — 1200 — goes to eiderdown, which comes from the Common Eider duck. Eiderdown tends to be expensive.
Answer:
13.875 T
Explanation:
Parameters given:
Length of solenoid, L = 2.5 cm = 0.025 m
Radius of solenoid, r = 0.75 cm = 0.0075 m
Number of turns, N = 25 turns
Current, I = 1.85 A
Magnetic field, B, is given as:
B = (N*r*I) /L
B = (25 * 0.0075 * 1.85)/0.025
B = 13.875 T
Answer:
Onda electromagnética
Explanation:
Las ondas mecánicas requieren un medio material para la propagación, mientras que las ondas electromagnéticas no requieren un medio material para la propagación.
Generalmente, las ondas electromagnéticas se mueven con una velocidad muy alta.
Todas las ondas electromagnéticas se denominan colectivamente luz y tienen una velocidad común de 3 × 10 ^ 8 m / s en el aire.
Ninguna onda mecánica tiene una velocidad tan alta en el aire.