A 20 kg crate of books is at rest on a table. what is the normal force on the books?
Answers
The weight of 20 kg is
(mass) x (gravity) =
(20 x 9.8) = 196 newtons, downward.
There must be a force of 196 newtons upward on the mass.
Otherwise the mass is accelerating either up or down.
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The work done by stretching a certain spring increases by 0.13x joules per centimeter (where x is the displacement, in centimeters, beyond the spring's natural length). How much work (in Joules) must be done in order to stretch the spring from x?
What happens in terms of energy when a moving car hits a parked car, causing the parked car to move?
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IWhat is your mass in kilograms of you weigh 120 pounds?
Answers
Answer: Microwaves
Explanation:
RADAR stands for radio detection and ranging. Radio waves range from 300 GHz to 30 Hz. Modern radar uses higher frequency of waves for detection. These waves are microwaves (300 MHz-300 GHz). Microwaves are types of radio waves and are used in the radar detection.
The electromagnetic wave which has highest frequency is gamma wave but it is not used for radar detection.
Hence, the correct answer is microwaves are the type pf radio waves which have the highest frequency and are used in radar detection.
Answers
The correct answer to the question is - Deposition i.e the process by which a gas changes to a solid is called deposition.
EXPLANATION:
There are various thermal processes of state or phase change in which matter in one state is converted into matter in another state.
Deposition is the type of thermodynamic process of state or phase change in which a gaseous substance is directly converted into corresponding solid substance without entering into liquid phase.
During this process, the loss of thermal energy from gas is very fast. Hence, the gas directly enters solid phase without undergoing into liquid phase.
This process is just the opposite process of sublimation where a solid is converted into gas directly. That's why this process is also known as desublimation.
For instance, conversion of water vapor into ice.
Answers
X - rays are considered an oxidizing mutagenic agent. X-rays are high energy electrons that can cause damage when exposed under extreme conditions. The best technology that can block it is t using a lightweight type of metal foam. It can take in high energy collisions which also exhibits high forces. it does not only block x-rays but also, neutron radiation and gamma rays.
Answers
Answer:
0.87
Explanation:
Given :
Mass of bottle = 29.2 g
Mass when filled with diesel = 116.2 g
Mass when filled with water = 129.2 g
The mass of water = (Mass when filled with water - mass of bottle)
Mass of water = 129.2 - 29.2 = 100 g
Mass of diesel = (Mass when filled with diesel - mass of bottle)
Mass of diesel = 116.2 - 29.2 = 87
Relative density of diesel = mass of diesel / mass of equal volume of water
Relative density = 87 / 100 = 0.87
Answers
It is not possible for a heat engine to be 100% efficient. The Laws of Thermodynamics explicitly explains that you can never transfer heat perfectly simply because during the flow of heat (either at low or high temperature) some of the initial input heat have been transformed into work.
Answers
So far we have been emphasizing how, at a fundamental level, the generation and propagation of gravitational and electromagnetic radiation are basically quite similar. This is a major point in demystifying gravitational waves. But, on a more practical level, gravitational and electromagnetic waves are quite different: we see and use electromagnetic waves every day, while we have yet to make a confirmed direct detection of gravitational waves (which is why they seemed so mysterious in the first place).
There are two principal differences between gravity and electromagnetism, each with its own set of consequences for the nature and information content of its radiation, as described below.
Gravity is a weak force, but has only one sign of charge.Electromagnetism is much stronger, but comes in two opposing signs of charge.
This is the most significant difference between gravity and electromagnetism, and is the main reason why we perceive these two phenomena so differently. It has several immediate consequences:Significant gravitational fields are generated by accumulating bulk concentrations of matter. Electromagnetic fields are generated by slight imbalances caused by small (often microscopic) separations of charge.Gravitational waves, similarly, are generated by the bulk motion of large masses, and will have wavelengths much longer than the objects themselves. Electromagnetic waves, meanwhile, are typically generated by small movements of charge pairs within objects, and have wavelengths much smaller than the objects themselves.Gravitational waves are weakly interacting, making them extraordinarily difficult to detect; at the same time, they can travel unhindered through intervening matter of any density or composition. Electromagnetic waves are strongly interacting with normal matter, making them easy to detect; but they are readily absorbed or scattered by intervening matter.
Gravitational waves give holistic, sound-like information about the overall motions and vibrations of objects. Electromagnetic waves give images representing the aggregate properties of microscopic charges at the surfaces of objects.
Gravitational charge is equivalent to inertia.
Electromagnetic charge is unrelated to inertia.
This is the more fundamental difference between electromagnetism and gravity, and influences many of the details of gravitational radiation, but in itself is not responsible for the dramatic differences in how we perceive these two types of radiation. Most of the consequences of the principle of equivalence in gravity have already be discussed, such as:The fundamental field of gravity is a gravitational force gradient (or tidal) field, and requires an apparatus spread out over some distance in order to detect it. The fundamental field in electromagnetism is an electric force field, which can be felt by individual charges within an apparatus.The dominant mode of gravitational radiation is quadrupolar: it has a quadratic dependence on the positions of the generating charges, and causes a relative "shearing" of the positions of receiving charges. The dominant mode of electromagnetic radiation is dipolar: it has a linear dependence on the positions of the generating charges, and creates a relative translation of the positions of receiving charges.
Answer:
1) Gravitational force and electromagnetic force both are field forces which means both forces exerted from long range of distance and we do not require any physical contact to apply these type of forces.
2) Now we also know that
both the forces are inversely depends on the square of the distance between two charges or two masses
so both forces follow inverse square law.
Now two ways they are alike is
1) gravitational force never exist in form of repulsive force while electromagnetic force is either repulsive or attractive.
2) Gravitational force is independent of the medium between two masses while electromagnetic force is dependent on the medium between two charges