When an object is protected upwards from the surface of a planet, it may return to the surface of the planet or it may revolve around the planet in a circular orbit or an elliptical orbit or it may escape from the gravitational influence of the planet following a parabolic or rectangular hyperbolic path.
Introduction to the Earth Escape Velocity
The velocity required by an object to revolve round a planet in a circular orbit is orbital velocity and the velocity required for an object to escape from the gravitational influence of the planet is escape velocity.
The minimum vertical velocity required for an object to escape from the gravitational influence of a planet is known as escape velocity. It is denoted by Ve . Having problem with Longitudinal Waves Definition keep reading my upcoming posts, i will try to help you.
Escape Velocity of from Earth : Derivation
Consider an object of mass 'm' at rest on the surface of a planet of mass m and radius R.
The gravitational potential on the surface of a planet = - `(GM)/(R)`
If we imagine that the object of mass m is brought from infinity to the surface of the lanet, the work done is stored as gravitational potential energy of the planet-object system.
`:.` The gravitational potential energy of the system = gravitational potential x mass of the object
= `(-GMm)/(R)` .
Negative sign indicates that the object is attracted by the planet and the object is bound to the planet. The object can be made to escape from the gravitational field of the planet by imparting certain minimum speed to the object. This minimum speed to be imparted to the bound object at rest is escape velocity ve . The kinetic energy imparted to the object must be equal and opposite to the potential energy of the system so that the total energy is equal to zero. Please express your views of this topic Friction Formula by commenting on blog.
`(1)/(2)` mve2 = - [ `(-GMm)/(R)` ].
`(1)/(2)` mve2 = `(GMm)/(R)`
`:.` Ve= `sqrt((2GM)/(R))`
In terms of g, the expression for Ve is
Ve= `sqrt((2GM)/(R))` = `sqrt((2gR^2)/(R))`
Ve = `sqrt(2gR)`
Earth Escape Velocity : Characteristics
The escape velocity does not depend on the mass of the body. Hence from a minute atom to mighty rocket, every object will have the same escape velocity irrespective of its mass, for a particular planet. It is also independent of angle of projection. But it depends on the mass of the planet, radius of the planet.
Molecules present in the atmosphere always move with a certain mean velocity. It depends upon the nature and temperature of surroundings. The escape velocity of an object on planet earth is as follows :
Radius of earth = 6.4 x 106 m , Acceleration due to gravity(g) = 9.8 m/s2 .,
Escape velocity Ve = `sqrt(2gR)`
= `sqrt(2 xx 9.8 xx 6.4 xx 10^6 m/s)`
= 11.2 x 103 m/s = 11.2 km/s
If a body is projected with a velocity greater than or equal to 11.2 km/s, it will never return to the earth.
Thursday, December 27, 2012
Electric and Magnetic Energy
INTRODUCTION TO ELECTRIC ENERGY AND MAGNETIC ENERGY
Electric field is created by both positive charges and negative charges. Positive charges have electric field that radiate outward and negative charges have electric field that radiate inward. These fields are created by the alternating currents that produce alternating electric fields. If current passes through any electrical appliance, then a part of electric energy is converted into electric current. Electric energy is the potential energy that is associated with the conservative coulomb forces within a well-defined system of point charges.
The amount of electric energy due to the electric current is represented by the expression Understanding Electromagnetic Pulse Effects is always challenging for me but thanks to all math help websites to help me out.
E = QV = VIt = I2Rt
where V is the electric potential difference(in volts) and Q is the charge(in coulombs). Electric energy is measured in joules. Magnetic fields radiate from north poles to south poles. Magnetic energy is defined as the potential energy of a magnet of magnetic moment m in magnetic field B. It is the work of magnetic force on the re-alignment of the vector of the magnetic dipole moment. Expression of the magnetic energy is represented as
Ep,m = - m.B
How are Electric and Magnetic Energy Related
Both the magnetic energy and the electric energy are related by the Maxwell’s equations. Wherever electricity is present , there also exist both electric energy and magnetic energy since the invisible lines of force creates electric charges. Electric fields are resulted from the strength of the charge while the magnetic fields are resulted from the motion of charge. Strengths of both electric and magnetic fields decreases when one moves away from the source of these fields. Magnetic energy of an electric current tends to conserve the electric current. The current will decline in time only when there is electric or magnetic resistance and the magnetic energy will be lost and the electric current also decreases eventually. Electric energy plays a crucial role in lighting, computer operations, entertainment applications, cooking, space heating and so on. Magnetic generators, magnetic motors, magnetic light box etc are the devices that are intended to use renewable magnetic energy and later recycles the energy back into the environment without any pollution. Magnetic energy also supplies light, heat and water needs. It can also be used to conserve our natural resources.
Is this topic Kinematics Equation hard for you? Watch out for my coming posts.
Electric field is created by both positive charges and negative charges. Positive charges have electric field that radiate outward and negative charges have electric field that radiate inward. These fields are created by the alternating currents that produce alternating electric fields. If current passes through any electrical appliance, then a part of electric energy is converted into electric current. Electric energy is the potential energy that is associated with the conservative coulomb forces within a well-defined system of point charges.
The amount of electric energy due to the electric current is represented by the expression Understanding Electromagnetic Pulse Effects is always challenging for me but thanks to all math help websites to help me out.
E = QV = VIt = I2Rt
where V is the electric potential difference(in volts) and Q is the charge(in coulombs). Electric energy is measured in joules. Magnetic fields radiate from north poles to south poles. Magnetic energy is defined as the potential energy of a magnet of magnetic moment m in magnetic field B. It is the work of magnetic force on the re-alignment of the vector of the magnetic dipole moment. Expression of the magnetic energy is represented as
Ep,m = - m.B
How are Electric and Magnetic Energy Related
Both the magnetic energy and the electric energy are related by the Maxwell’s equations. Wherever electricity is present , there also exist both electric energy and magnetic energy since the invisible lines of force creates electric charges. Electric fields are resulted from the strength of the charge while the magnetic fields are resulted from the motion of charge. Strengths of both electric and magnetic fields decreases when one moves away from the source of these fields. Magnetic energy of an electric current tends to conserve the electric current. The current will decline in time only when there is electric or magnetic resistance and the magnetic energy will be lost and the electric current also decreases eventually. Electric energy plays a crucial role in lighting, computer operations, entertainment applications, cooking, space heating and so on. Magnetic generators, magnetic motors, magnetic light box etc are the devices that are intended to use renewable magnetic energy and later recycles the energy back into the environment without any pollution. Magnetic energy also supplies light, heat and water needs. It can also be used to conserve our natural resources.
Is this topic Kinematics Equation hard for you? Watch out for my coming posts.
Thursday, December 20, 2012
Echo Sounding
Introduction to echo sounding:
Sound waves undergo reflections and obey the laws of reflection. Big walls and auditorium with parabolic smooth surfaces, well polished surfaces and metal surfaces are good reflectors of sound. Cello tape, thermocol, cushions, wall hangings and human beings are good absorbers of sound.
Definition of Echo Sounding:
An echo is a sound repeated by reflection from the surfaces of obstacles.
Reflection of sound in a large empty hall was due to the repeated hearings of sound. This phenomenon is called an echo and is due to the reflection of sound from the surface of obstacles.
The sensation of sound that lasts or persists in our brain for 0.1 second, even after the source of sound has stopped vibrating. Note that if we want to hear distinct echo, the reflected sound or echo must reach the echo 1/10 second or 0.1 second after the direct original sound. If we take the sound speed too be 330m/s, the sound must go to the obstacle and reach the ear of the listener on reflection after 0.1 s. This implies that the total distance covered should be at least 332 x 0.1 = 33.2 m. Thus for hearing distinct echoes, the minimum distance of the obstacle from the source of the sound must be half of the distance i.e., 16.6 m from the source. In a small room, whose walls as the reflecting obstacles, are less than 16.6 m away, no echo is possible. In this case, the original direct sound gets merged into the reflected sound and a sustained sound is heard which is called reverberation.
Echo Sounding:
Echoes may be heard more than once. Multiply echoes may be heard, one after another, when sound is repeatedly reflected from a number of obstacles such as two parallel distinct buildings on cliffs. The phenomenon of echoe’s is used in measuring distance in determining the ocean depths and in locating the presence of under-water objects.
Sound waves undergo reflections and obey the laws of reflection. Big walls and auditorium with parabolic smooth surfaces, well polished surfaces and metal surfaces are good reflectors of sound. Cello tape, thermocol, cushions, wall hangings and human beings are good absorbers of sound.
Definition of Echo Sounding:
An echo is a sound repeated by reflection from the surfaces of obstacles.
Reflection of sound in a large empty hall was due to the repeated hearings of sound. This phenomenon is called an echo and is due to the reflection of sound from the surface of obstacles.
The sensation of sound that lasts or persists in our brain for 0.1 second, even after the source of sound has stopped vibrating. Note that if we want to hear distinct echo, the reflected sound or echo must reach the echo 1/10 second or 0.1 second after the direct original sound. If we take the sound speed too be 330m/s, the sound must go to the obstacle and reach the ear of the listener on reflection after 0.1 s. This implies that the total distance covered should be at least 332 x 0.1 = 33.2 m. Thus for hearing distinct echoes, the minimum distance of the obstacle from the source of the sound must be half of the distance i.e., 16.6 m from the source. In a small room, whose walls as the reflecting obstacles, are less than 16.6 m away, no echo is possible. In this case, the original direct sound gets merged into the reflected sound and a sustained sound is heard which is called reverberation.
Echo Sounding:
Echoes may be heard more than once. Multiply echoes may be heard, one after another, when sound is repeatedly reflected from a number of obstacles such as two parallel distinct buildings on cliffs. The phenomenon of echoe’s is used in measuring distance in determining the ocean depths and in locating the presence of under-water objects.
Potato Battery Light Bulb
Introduction to potato battery light bulb
We can use potato to produce electricity or to light a light bulb and it is known as Potato battery light bulb. The principle of an electrochemical cell is made use in a Potato battery light bulb. Chemical energy is transformed into electricity (electrical energy). The zinc and the copper acts as the anode and cathode terminals of the potato battery. A metal coin (copper) and a galvanized nail are used for this purpose. A tomato, lemon or other citrus fruit can be substituted for Potato to produce electricity. With the help of ordinary electrical wires, the potato can be used to create a voltaic cell, which will power a very small bulb or a light emitting diode (LED). A LED Clock or a calculator also can be made working using the Potato battery. Understanding Wavelength of Ultraviolet Light is always challenging for me but thanks to all math help websites to help me out.
Materials Required to Make a Potato Battery Light Bulb
Materials required to make a Potato battery light bulb are 2 Potatoes, 2 galvanized nails or galvanized screws (act as zinc electrode), 2 copper coins or 2 thick copper wires (act as copper electrode), Three connecting copper wires ( with alligator clip preferred) and an LED Bulb.
Procedure to Make a Potato Battery Light Bulb
First step is to take a potato and insert the coin (copper electrode) and galvanized nail or screw (Zinc electrode) at a distance. The zinc and copper electrodes should not be touched each other. Repeat the same for another Potato. Then, one end of one of the three copper connecting wires is to be connected to the copper coin of one potato and the other end to the galvanized nail or screw of the second potato. Then, one end of the second and third connecting copper wires should be connected to the galvanized nail or screw of the first potato and to the copper coin of the second potato respectively. Then the other ends of the second and third copper connecting wires can be connected to the LED Bulb. (Or to ammeter to measure the electric current produced). So we get electricity out of just 2 potatoes and a couple of bits of metal.
But this kind of battery generally produces only a few milliards. So, in order to get enough voltage, 2 or 3 potatoes can be put in a raw (series connection) and in order to get enough current, a bunch can be connected in parallel. Is this topic formula Fahrenheit to celsius hard for you? Watch out for my coming posts.
Working of Potato Battery Light Bulb
Electric current is produced by the movement of electrons from one atom to another in a conductor. The insertion of two common metal electrodes into the potato causes a chemical reaction to occur resulting in current. The potatoes do not participate directly in the reaction. It acts as an electrolyte for the transport of the zinc and copper ions in the solution, while keeping the copper and zinc electrodes apart. The electro-chemical reaction of zinc with copper is due to the presence of Phosphoric acid (or H3PO4) in potato. Zinc is an active metal and it reacts readily with acid to liberate electrons. At the metal coin (Copper electrode), electrons from the copper attaches to the hydrogen ions in the phosphoric acid which depletes the electrons.
We can use potato to produce electricity or to light a light bulb and it is known as Potato battery light bulb. The principle of an electrochemical cell is made use in a Potato battery light bulb. Chemical energy is transformed into electricity (electrical energy). The zinc and the copper acts as the anode and cathode terminals of the potato battery. A metal coin (copper) and a galvanized nail are used for this purpose. A tomato, lemon or other citrus fruit can be substituted for Potato to produce electricity. With the help of ordinary electrical wires, the potato can be used to create a voltaic cell, which will power a very small bulb or a light emitting diode (LED). A LED Clock or a calculator also can be made working using the Potato battery. Understanding Wavelength of Ultraviolet Light is always challenging for me but thanks to all math help websites to help me out.
Materials Required to Make a Potato Battery Light Bulb
Materials required to make a Potato battery light bulb are 2 Potatoes, 2 galvanized nails or galvanized screws (act as zinc electrode), 2 copper coins or 2 thick copper wires (act as copper electrode), Three connecting copper wires ( with alligator clip preferred) and an LED Bulb.
Procedure to Make a Potato Battery Light Bulb
First step is to take a potato and insert the coin (copper electrode) and galvanized nail or screw (Zinc electrode) at a distance. The zinc and copper electrodes should not be touched each other. Repeat the same for another Potato. Then, one end of one of the three copper connecting wires is to be connected to the copper coin of one potato and the other end to the galvanized nail or screw of the second potato. Then, one end of the second and third connecting copper wires should be connected to the galvanized nail or screw of the first potato and to the copper coin of the second potato respectively. Then the other ends of the second and third copper connecting wires can be connected to the LED Bulb. (Or to ammeter to measure the electric current produced). So we get electricity out of just 2 potatoes and a couple of bits of metal.
But this kind of battery generally produces only a few milliards. So, in order to get enough voltage, 2 or 3 potatoes can be put in a raw (series connection) and in order to get enough current, a bunch can be connected in parallel. Is this topic formula Fahrenheit to celsius hard for you? Watch out for my coming posts.
Working of Potato Battery Light Bulb
Electric current is produced by the movement of electrons from one atom to another in a conductor. The insertion of two common metal electrodes into the potato causes a chemical reaction to occur resulting in current. The potatoes do not participate directly in the reaction. It acts as an electrolyte for the transport of the zinc and copper ions in the solution, while keeping the copper and zinc electrodes apart. The electro-chemical reaction of zinc with copper is due to the presence of Phosphoric acid (or H3PO4) in potato. Zinc is an active metal and it reacts readily with acid to liberate electrons. At the metal coin (Copper electrode), electrons from the copper attaches to the hydrogen ions in the phosphoric acid which depletes the electrons.
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