Physics · Grades 8–11
Interaction pairs act on different objects · Revision sheet
Identify equal-and-opposite pairs without cancelling the wrong forces.
Learn the idea
Interaction
If A exerts a force on B, B exerts an equal-magnitude opposite-direction force on A.
Different objects
The two forces act on different bodies, so they do not cancel in a force sum for only one body.
Different accelerations
Equal interaction forces can produce different accelerations when the masses differ.
Name both bodies
Describe a pair as force of A on B and force of B on A rather than vaguely calling them two balanced forces.
Explain without looking
- Two carts of mass 2 kg and 6 kg feel interaction forces of magnitude 12 N. Find the 2 kg cart's acceleration magnitude.
- Write a complete interaction pair for a foot pushing backward on the ground.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.