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Name: pete
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 1999 

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?

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

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