Forces on an object falling to earth Question

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SUMMARY

The discussion centers on the forces acting on an object falling toward Earth, specifically addressing the application of Newton's third law of motion. The correct answer to the posed question is that the upward acceleration of Earth is negligible due to its large mass. Participants clarified that while both the object and Earth exert gravitational forces on each other, the Earth's mass results in an imperceptible acceleration in response to the object's fall. This reinforces the principle that every action has an equal and opposite reaction, but the effects vary significantly based on mass.

PREREQUISITES
  • Understanding of Newton's third law of motion
  • Basic knowledge of gravitational force and its formula, F = (G*m1*m2)/r^2
  • Familiarity with concepts of mass and acceleration
  • Awareness of the implications of large mass on force interactions
NEXT STEPS
  • Study the implications of Newton's laws in different gravitational contexts
  • Explore the concept of gravitational force in detail, including variations with distance
  • Investigate the effects of mass on acceleration in various physical scenarios
  • Learn about the mathematical modeling of forces in physics simulations
USEFUL FOR

Students studying physics, educators teaching Newtonian mechanics, and anyone interested in understanding gravitational interactions and forces in motion.

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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