Finding initial speed given final speed

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Homework Help Overview

The problem involves calculating the initial speed required for an object launched from Mercury to achieve a specified final speed when far from the planet. The context is rooted in gravitational physics and conservation of energy principles.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of conservation of energy in the context of escape speed and initial speed calculations. Questions arise regarding the necessary conditions for these calculations, particularly when the final speed at infinity is not zero.

Discussion Status

Some participants have raised concerns about the accuracy of the mass value provided for Mercury, suggesting a potential typo. The discussion is exploring the implications of these values on the calculations being attempted.

Contextual Notes

There is a noted discrepancy in the mass of Mercury, which is critical for the calculations. Participants are questioning the assumptions made regarding the values used in the problem setup.

jamagner
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The radius of Mercury (from the center to just above the atmosphere) is 2440 km (2440103 m), and its mass is 0.31024 kg. An object is launched straight up from just above the atmosphere of Mercury.
(a) What initial speed is needed so that when the object is far from Mercury its final speed is 2500 m/s?

the second part is about the escape speed which i already figured out
 
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This is another conservation of energy problem.
 
jamagner said:
The radius of Mercury (from the center to just above the atmosphere) is 2440 km (2440103 m), and its mass is 0.31024 kg.

Check your values, by the way. Mercury certainly has more mass than 0.3 kg...

What needs to be different about using conservation of energy to solve for the escape speed versus solving for the starting speed when the speed at infinity is greater than zero?
 
dynamicsolo said:
Check your values, by the way. Mercury certainly has more mass than 0.3 kg...
:smile: A typo, I presume. More like 0.3x10^24 kg.
 

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