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Newton's First & Second Laws

CONCEPTUAL
Science›Forces & Motion|Ages 12—13|ID: mt_tXxxCFl32J

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 [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?”

Curriculum Standards3 alignments

MS-PS2-1Next Generation Science Standards (NGSS) Middle Schoolcodes only
Standard code — full text not included in this dataset.
MS-PS2-2Next Generation Science Standards (NGSS) Middle Schoolcodes only
Standard code — full text not included in this dataset.
KS3.Sci.Phys.MotionAndForces.7The national curriculum in England
Newton's Laws of Motion

forces and Newton's Laws: Newton's First Law; forces and acceleration (Newton's Second Law); Newton's Third Law

Science · KS3

Prerequisites3

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  • Resultant Forces hard

    Newton's 1st and 2nd laws are defined in terms of resultant force — the concept of balanced and unbalanced forces must be understood first

    • Pushes & Pulls hard

      KS3 forces as vectors extends KS2 introduction to pushes and pulls changing speed and direction

      • Drawing Force Diagrams soft

        Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

    • Force & Motion Vocabulary hard

      Describing balanced and unbalanced forces as vector quantities requires resultant force, balanced forces vocabulary

    • Drawing Force Diagrams hard

      Forces as vectors with magnitude and direction is the formal underpinning of the force arrow representation

    • Contact & Non-Contact Forces hard

      KS3 resultant force and balanced forces extends KS2 distinction between contact and non-contact forces

      • Forces Vocabulary hard

        Distinguishing contact from non-contact forces requires these exact terms

      • Drawing Force Diagrams soft

        Distinguishing contact and non-contact forces is clarified by drawing force diagrams showing where arrows originate

      • Friction & Surfaces hard

        Must experience contact forces like friction before distinguishing contact vs non-contact forces

        • Pushes & Pulls hard

          Must understand forces change motion before comparing movement on different surfaces

          • Drawing Force Diagrams soft

            Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

        • Forces Vocabulary hard

          Comparing how things move on different surfaces requires friction vocabulary

  • Mass vs Weight soft

    Gravity (weight = mg) is the main worked example for Newton's laws — mass/weight distinction gives concrete numbers for F = ma

    • Gravity & Falling Objects hard

      KS3 weight = mass × g extends KS2 introduction to gravity as the force pulling objects toward Earth

      • Balanced & Unbalanced Forces soft

        Balanced/unbalanced forces supports understanding gravity as an unbalanced force on unsupported objects

        • Pushes & Pulls hard

          Must understand pushes/pulls before investigating balanced vs unbalanced forces

          • Drawing Force Diagrams soft

            Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

        • Drawing Force Diagrams hard

          Investigating balanced and unbalanced forces requires drawing force diagrams to record and analyse experimental findings

        • Friction & Surfaces hard

          Must understand friction affects motion before investigating balanced/unbalanced forces

          • Pushes & Pulls hard

            Must understand forces change motion before comparing movement on different surfaces

            • Drawing Force Diagrams soft

              Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

          • Forces Vocabulary hard

            Comparing how things move on different surfaces requires friction vocabulary

      • Forces Vocabulary hard

        Explaining gravity requires the force vocabulary: gravity, weight, non-contact force

      • Drawing Force Diagrams hard

        Explaining gravity as a downward force requires representing it as a downward arrow in a force diagram

      • Contact & Non-Contact Forces hard

        Must know about non-contact forces before learning gravity as a non-contact force

        • Forces Vocabulary hard

          Distinguishing contact from non-contact forces requires these exact terms

        • Drawing Force Diagrams soft

          Distinguishing contact and non-contact forces is clarified by drawing force diagrams showing where arrows originate

        • Friction & Surfaces hard

          Must experience contact forces like friction before distinguishing contact vs non-contact forces

          • Pushes & Pulls hard

            Must understand forces change motion before comparing movement on different surfaces

            • Drawing Force Diagrams soft

              Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

          • Forces Vocabulary hard

            Comparing how things move on different surfaces requires friction vocabulary

  • Air Resistance & Friction soft

    Newton's laws explain why friction and air resistance slow objects down — the KS2 observation of resistance now has a theoretical explanation

    • Gravity & Falling Objects soft

      Understanding gravity helps contextualise resistive forces opposing gravitational motion

      • Balanced & Unbalanced Forces soft

        Balanced/unbalanced forces supports understanding gravity as an unbalanced force on unsupported objects

        • Pushes & Pulls hard

          Must understand pushes/pulls before investigating balanced vs unbalanced forces

          • Drawing Force Diagrams soft

            Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

        • Drawing Force Diagrams hard

          Investigating balanced and unbalanced forces requires drawing force diagrams to record and analyse experimental findings

        • Friction & Surfaces hard

          Must understand friction affects motion before investigating balanced/unbalanced forces

          • Pushes & Pulls hard

            Must understand forces change motion before comparing movement on different surfaces

            • Drawing Force Diagrams soft

              Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

          • Forces Vocabulary hard

            Comparing how things move on different surfaces requires friction vocabulary

      • Forces Vocabulary hard

        Explaining gravity requires the force vocabulary: gravity, weight, non-contact force

      • Drawing Force Diagrams hard

        Explaining gravity as a downward force requires representing it as a downward arrow in a force diagram

      • Contact & Non-Contact Forces hard

        Must know about non-contact forces before learning gravity as a non-contact force

        • Forces Vocabulary hard

          Distinguishing contact from non-contact forces requires these exact terms

        • Drawing Force Diagrams soft

          Distinguishing contact and non-contact forces is clarified by drawing force diagrams showing where arrows originate

        • Friction & Surfaces hard

          Must experience contact forces like friction before distinguishing contact vs non-contact forces

          • Pushes & Pulls hard

            Must understand forces change motion before comparing movement on different surfaces

            • Drawing Force Diagrams soft

              Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

          • Forces Vocabulary hard

            Comparing how things move on different surfaces requires friction vocabulary

    • Forces Vocabulary hard

      Identifying air resistance, water resistance, and friction requires these force terms

    • Drawing Force Diagrams hard

      Identifying and explaining air resistance and friction requires drawing force arrows to show opposing forces

    • Friction & Surfaces hard

      Must know friction from surface comparisons before learning about air/water resistance as similar forces

      • Pushes & Pulls hard

        Must understand forces change motion before comparing movement on different surfaces

        • Drawing Force Diagrams soft

          Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction

      • Forces Vocabulary hard

        Comparing how things move on different surfaces requires friction vocabulary

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