Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Balanced Forces 
Name: pete
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 1999
Question:
If a car accelerates because there is an balanced force acting on it how can it move if for every action there is an equal and opposite reaction?

Replies:
Unbalanced forces would be peculiar, indeed! Let us take two objects, say a horse and planet earth. The horse pushes backward against the earth, and the earth pushes the horse forward with exactly the same magnitude force.

F horse = F earth

mA = Ma

In the horse-earth system, the large mass of the earth results in a small acceleration of the earth, where the small mass of the horse results in a large acceleration.

---Nathan A. Unterman


Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory