Interaction — Science definition
Mutual influence between named objects.
Where it is taught
- Interaction Pairs & Force Diagrams — Forces, Physical Science: Matter, Forces & Energy, Grade 8
In use
This prevents the common error of putting an equal-and-opposite interaction pair on the same object and concluding that all motion must be impossible.
Interaction Pairs & Force Diagrams
Questions using interaction
Problem 1
In an illustrative interaction a hand pushes a cart rightward with 8 N. Floor resistance on the cart is 3 N leftward. State the cart’s horizontal net force and the cart-on-hand force; explain why they differ.
Answer and explanation
The cart’s net force is 8−3=5 N rightward. The cart pushes the hand with 8 N leftward as the partner of the hand-on-cart interaction. The 3 N floor force belongs to another interaction. Net force on the cart and the pair force on the hand answer different questions.
The cart’s net force is 8−3=5 N rightward. The cart pushes the hand with 8 N leftward as the partner of the hand-on-cart interaction. The 3 N floor force belongs to another interaction. Net force on the cart and the pair force on the hand answer different questions.
Response criteria
- Use the supplied conditions and relevant evidence.
- Explain the scientific mechanism or calculation.
- State a meaningful limitation or testable next step.