What is the total resistance of the circuit shown above?
1 answer:
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Answer:
gamma rays , X rays, ultraviolet , visible light , infrared, radio waves
Explanation:
The electromagnetic spectrum is the set of electromagnetic radiations distributed in their different frequencies or wavelengths, which in turn are related to their energy. If we go from the smallest wavelengths known up to now (because according to physics the electromagnetic spectrum is infinite and continuous) to the longest, the electromagnetic spectrum covers the following radiations:
Gamma rays, X-rays, ultraviolet, visible light (all the colors we are able to see), infrared, radio waves and microwaves.
Let's make a brief of them:
-Gamma rays: With a wavelength in the order of , is a type of ionizing radiation capable of penetrating matter quite deeply and is able to cause serious damage to the nucleus of the cells. Inaddiito, these rays are used to sterilize medical equipment and food.
-X rays: With a wavelength between and
. It is invisible to the human eye, capable of crossing opaque bodies and of being an ionizing radiation.
-Ultraviolet light: Whose wavelength is approximately between 100 nm and 380 nm; is a type of electromagnetic radiation that is not visible to the human eye.
-Visible light: This part of the spectrum is located between ultraviolet light and infrared light (380 nm - 780 nm). It should be noted, the fact the only part of the whole electromagnetic spectrum is visible to humans is because the receptors in our eyes are only sensitive to these wavelengths.
-Infrared: This type of radiation is not visible to the human eye, since its wavelengths are outside the visible spectrum (between 700 nm and 1 mm).
These waves can be divided into:
<u>- Near infrared</u> or long wave infrared: it is the least sensitive to color and is easily absorbed by water.
<u>- Medium or medium wave infrared:</u> it is also insensitive to color and easily absorbed by water and many types of plastics and paints.
-<u> Far infrared or short wave infrared: </u>it is more penetrating than the long wave and is good for heating metals, these waves also can pass through clear materials.
This light has many uses, including heating lamps in physiotherapy and medical treatments, heat sensing devices, among others.
-Radio waves: These are a type of electromagnetic radiation with wavelengths between 10 m to 10,000 m. This type of electromagnetic waves is very well reflected in the ionosphere, the layer of the atmosphere through which they travel directly or using repeaters. In addition, they are very useful to transport information, being important in telecommunications. They are used not only for conventional radio transmissions but also in mobile telephony and TV.
Answer:
The blocks must be pushed with a force higher than 359 Newtons horizontally in order to accomplish this friction levitation feat.
Explanation:
The first step in resolving any physics problem is to draw the given scenario (if possible), see the attached image to have an idea of the objects and forces involved.
The large cube in red is being pushed from the left by a force whose value is to be found. That cube has its own weight
, and it is associated with the force of gravity which points downward. Newton's third law stipulates that the response from the floor is an upward pointing force on the cube, and it's called the normal force
.
A second cube is being pushed by the first, and since the force is strong enough it is able to keep such block suspended as if it were glued to the first one, due to friction. As in the larger cube, the smaller one has a weight
pointing downwards, but the normal force in this block doesn't point upwards since its 'floor' isn't below it, but in its side, therefore the normal force directs it to the right as it is shown in the picture. Normal forces are perpendicular to the surface they contact. The final force is the friction between both cubes, that sets a resistance of one moving parallel the other. In this case, the weight of the block its the force pointing parallel to the contact surface, so the friction opposes that force, and thus points upwards. Friction forces can be set as
, where
is the coefficient of static friction between the cubes.
Now that all forces involved are identified, the following step is to apply Newton's second law and add all the forces for each block that point in the same line, and set it as equal its mass multiplied by its acceleration. The condition over the smaller box is the relevant one so its the first one to be analyzed.
In the vertical component: Since the idea is that it doesn't slips downwards, the vertical acceleration should be set to zero
, and making explicit the other forces:
[N]. In the last equation gravity's acceleration was rounded to 10 [m/s
].
In its horizontal component: , this time the horizontal acceleration is not zero, because it is constantly being pushed. However, the value of the normal force and the mass of the block are known, so its horizontal acceleration can be determined:
[m/s
]. Notice that this acceleration is higher than the one of gravity, and it is understandable since you should be able to push it harder than gravity in order for it to not slip.
Now the attention is switched to the larger cube. The vertical forces are not relevant here, since the normal force balances its weight so that there isn't vertical acceleration. The unknown force comes up in the horizontal forces analysis: , since the force
is not only pushing the first block but both, the mass involved in this equation is the combined masses of the blocks, the acceleration is the same for both blocks since they move together;
[N]. The resulting force is quite high but not impossible to make by a human being, this indicates that this feat of friction suspension is difficult but feasable.
Answer:
Explanation:
F = Magnetic force = 0.018 N
B = Magnetic field = 0.03 T
L = Length of wire = 35 cm
= Angle between current and magnetic field =
Magnetic force is given by
The magnitude of the current is .