Mechanical Energy Homework: Zero Planet w/ 10kg Probe Launch

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SUMMARY

The discussion centers on calculating the kinetic energy of a 10 kg probe launched from the surface of a hypothetical planet named Zero, which has a mass of 1.0x1023 kg and a radius of 3.0x106 m. The probe is launched with an initial kinetic energy of 5.0x107 J, and the objective is to determine its kinetic energy when it is 4.0x106 m from the center of Zero. The relevant equation used is (1/2)mv2 - (GMm/R) = (1/2)mv2 - (GMm)/(10R), where G is the gravitational constant (6.67e-11). The discussion highlights confusion regarding the correct value of R and the interpretation of distances in the equation.

PREREQUISITES
  • Understanding of gravitational potential energy and kinetic energy concepts
  • Familiarity with the gravitational constant (G = 6.67e-11 N(m/kg)2)
  • Knowledge of the equations of motion in a gravitational field
  • Ability to manipulate algebraic equations involving physical constants
NEXT STEPS
  • Review gravitational potential energy calculations in non-atmospheric conditions
  • Study the derivation and application of the conservation of mechanical energy principle
  • Learn about the implications of distance measurements in gravitational equations
  • Explore the effects of varying mass and radius on gravitational force and energy
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and gravitational forces, as well as educators seeking to clarify concepts related to energy conservation in gravitational fields.

norcal
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Homework Statement



Zero, a hypothetical planet, has a mass of 1.0x10^23 kg, a radius of 3.0x10^6 m, and no atmosphere. A 10 kg space probe is to be launched vertically from its surface.
(a) If the probe is launched with an initial kinetic energy of 5.0x10^7 J, what will be its kinetic energy when it is 4.0x10^6 m from the center of Zero?

Homework Equations



(1/2)mv^2 - (GMm/R)=(1/2)mv^2 - (GMm)/(10R)

The Attempt at a Solution



5.0e7 - [(6.67e-11)(1e23)(10)]/(3e6)= KE - [(6.67e-11)(1e23)(10)]/(10(4e6)]

I don't think that I am using the right values for R though. Am I?
 
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(1/2)mv^2 - (GMm/R) = (1/2)mv^2 - (GMm)/(10R)

I can't see where the 10R comes from. Should be R as on the LHS.
 
ok, well do I have the correct values of R set up in the equation or do I need to take the difference of the distance of the satellite to the center or anything?
 
I think all your distances are measured from the centre of Zero.
 

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