A.2.2—Forces as interactions between bodies Topic Practice
A.2.2—Forces as interactions between bodies Topic Practice
Practise treating every force as an interaction between two bodies, so you can identify paired forces and avoid mixing them with resultants.
How this is tested
- identify the Newton's third-law pair on a free-body diagram for contact or field interactions
- use F = ma for two touching blocks to decide the contact force one block exerts on the other
- state the model assumption that internal forces within one system do not change the system acceleration