Science
Forces & Motion
Conceptual
12–13 yrs
Newton's First & Second Laws
牛顿第一定律与第二定律
Description
State and apply Newton's First Law (an object stays at rest or constant velocity unless acted on by a resultant force) and Second Law (force = mass × acceleration), including the relationship between mass, force, and acceleration
Mastery Evidence
- States Newton's First Law and gives a real example (e.g. why a moving spacecraft doesn't need engines in space)
- Uses F = ma to calculate force, mass, or acceleration given the other two quantities
- Explains why a heavier object requires more force to achieve the same acceleration
- Explains why seatbelts are needed in cars using Newton's First Law
Assessment Prompt
If your child was asked why you need a seatbelt in a car but not when sitting still, could they explain what Newton's First Law says about moving objects — and then calculate how much force a 60 kg person experiences in a sudden stop?
