Mass and Radius of a Planet given v

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SUMMARY

The discussion focuses on calculating the mass and radius of Planet Physics using the equations of motion and gravitational dynamics. The initial velocity of a rock tossed upwards at 13 m/s and the time of 2.7 seconds provides the first equation, while the orbital period of a cruise ship at an altitude equal to the planet's radius (210 minutes) gives the second equation. The relevant formulas are M = v²r/G and M = 4π²r³/GT². By substituting values from one equation into the other, the mass and radius can be determined.

PREREQUISITES
  • Understanding of kinematic equations, specifically s = ut + ½at²
  • Familiarity with gravitational force equations, including M = v²r/G
  • Knowledge of orbital mechanics, particularly the relationship between period and radius
  • Basic algebra skills for solving equations and substituting variables
NEXT STEPS
  • Study kinematic equations in-depth, focusing on vertical motion analysis
  • Learn about gravitational dynamics and the derivation of M = v²r/G
  • Explore orbital mechanics, particularly the relationship between orbital period and radius
  • Practice solving problems involving multiple equations and variable substitution
USEFUL FOR

Students in physics, particularly those studying mechanics and gravitational forces, as well as educators looking for examples of problem-solving in planetary physics.

chitoboy18
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Homework Statement


While visiting Planet Physics, you toss a rock straight up at 13m/s and catch it 2.7s later. While you visit the surface, your cruise ship orbits at an altitude equal to the planet's radius every 210min . What is the mass and radius of the planet Physics?


Homework Equations



M=v^2r/G M=4pi^2r^3/GT^2

Please help me, I'm like so confused.
 
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chitoboy18 said:

Homework Statement


While visiting Planet Physics, you toss a rock straight up at 13m/s and catch it 2.7s later. While you visit the surface, your cruise ship orbits at an altitude equal to the planet's radius every 210min . What is the mass and radius of the planet Physics?


Homework Equations



M=v^2r/G M=4pi^2r^3/GT^2

Please help me, I'm like so confused.

You should not expect much help until you've tried a bit harder yourself.

You have two pieces of information, each of which gives you an equation to solve. When you've done that, you can substitute one in the other to get the answers. You also need [itex]s = ut + \frac{1}{2} at^2[/itex] for the first bit, and you need to work out how the orbit period relates to the speed and radius of orbit.
 

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