Newton's Third Law in Collisions
Aligned to MS-PS2-1 — Next Generation Science Standards.
What this lesson teaches
Newton's Third Law says every force comes in a pair. When two objects collide, each one pushes on the other with equal strength in opposite directions.
Worked example
When a moving bumper car hits a stopped one, the first car pushes the second forward and the second pushes back on the first with an equal force, so the first car slows down while the second speeds up.
Practice questions
- Observe two carts colliding and identify the action and reaction force pair.
- Design a bumper that reduces damage in a collision and explain which force it changes.
- Explain why both objects feel the same size force even when one is much heavier than the other.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
La Tercera Ley de Newton en Choques
La Tercera Ley de Newton dice que toda fuerza viene en pareja. Cuando dos objetos chocan, cada uno empuja al otro con la misma intensidad en direcciones opuestas.
Ejemplo: Cuando un carrito chocón en movimiento golpea a uno detenido, el primer carro empuja al segundo hacia adelante y el segundo empuja de regreso al primero con una fuerza igual, así que el primer carro se frena mientras el segundo se acelera.
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