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jsmith613
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can someone please very briefly explain why the escape velocity of an object is given when the total mechanical energy (KE + potential energy) on an object is zero
Thanks
Thanks
truesearch said:masses in a gravitational field have negative potential energy. The zero of potential energy is taken to be at infinity. To get to infinity energy must be supplied therefore objects must have negative potential energy. (if you have to add energy to get to zero...)
The energy supplied must total zero !
truesearch said:In a word...Yes, unless... you know different.
PE is a relative value between two points in space. KE is relative to some (inertial, non-accelerating) frame of reference. GPE is zero at infinity only when it's defined that way. For simple physics problems, GPE is often defined as zero at the surface of the Earth (GPE = m g h).jsmith613 said:all the KE is converted to GPE at infnity, at this inifinity point, GPE is zero
Escape velocity is the minimum speed an object needs to reach in order to escape the gravitational pull of a massive body, such as a planet or star. It is the speed at which an object would need to travel in a straight line, with no additional propulsion, to break free from the gravitational force holding it in orbit.
The formula for escape velocity is v=sqrt((2GM)/r), where v is the escape velocity, G is the gravitational constant, M is the mass of the massive body, and r is the distance between the object and the center of the massive body.
The two main factors that affect escape velocity are the mass of the massive body and the distance between the object and the center of the massive body. The greater the mass of the massive body, the higher the escape velocity required. Similarly, the closer an object is to the center of the massive body, the higher the escape velocity needed.
Orbital velocity is the speed at which an object needs to travel to maintain a stable orbit around a massive body. It is different from escape velocity because it takes into account the gravitational pull of the massive body and the centripetal force needed to maintain the orbit, while escape velocity only considers the gravitational pull.
Escape velocity plays a crucial role in space exploration as it determines the speed and trajectory needed for spacecraft to leave Earth's orbit and travel to other planets or celestial bodies. By calculating the escape velocity of different planets, scientists can determine the most efficient and effective routes for spacecraft to travel through space.