Forces on an object falling to earth Question

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Homework Help Overview

The discussion revolves around the forces acting on an object as it falls toward Earth, specifically addressing Newton's third law and the implications of gravitational forces between the object and Earth.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between the falling object and Earth, questioning the nature of the forces involved and the implications of Newton's third law. There is a discussion about why the Earth does not accelerate significantly despite the gravitational pull from the falling object.

Discussion Status

Some participants have provided insights into the gravitational interaction and the application of Newton's third law, while others are seeking clarification on the acceleration of Earth in response to the falling object. The conversation reflects a mix of understanding and confusion regarding the forces at play.

Contextual Notes

Participants are grappling with the assumptions related to gravitational forces and the effects of mass on acceleration, particularly in the context of homework constraints that may limit the depth of exploration.

asura
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Homework Statement



As an object falls toward Earth

a. the object does not exert a force on earth
b. the object exerts a downward force on earth
c. Newton's third law does not apply
d. the upward acceleration of Earth is negligible because of its large mass

Homework Equations



none

The Attempt at a Solution



I chose A, but the answer for this question is d. Can someone explain how Earth accelerates?
 
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Two bodies in space always exert a gravitational force on each other, F = (G*m1*m2)/r^2 which pulls each body towards the other... this is Newton's third law, the postulate of equal/opposite forces... if the Earth exerts on a gravitational force on a falling object, that same object must reciprocate and pull on the Earth as well. this force is just far too weak for the Earth to accelerate appreciably
 
Newton's third law. The object exerts a force on the Earth equal and opposite to the force the Earth exerts on the object. Now reconsider d). Why doesn't the Earth jump up to meet the object?
 
ok, I understand now. I forgot gravity also had an opposite force.

thanks
 

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