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8th grade · Science · Unit 3 of 11

Motion, Forces & Newton’s Laws

Speed, velocity, acceleration, friction and the Laws of Motion.

What your child practices

Practices speed, velocity, acceleration, forces, friction, gravity and Newton's three Laws of Motion, with stability. It follows the Grade 8 science skill descriptors on motion and stability and the Laws of Motion in the New Brunswick curriculum.

New York State Learning Standards learning standard: MS-PS2-1; MS-PS2-2 · Newton's laws, forces and changes in motion

How we explain it

Children can open this short lesson before they practice.

  1. Speed = distance ÷ time. Velocity is speed with a direction.
  2. Force is measured in newtons. Friction and gravity are forces.
  3. Newton’s laws: objects keep doing what they’re doing unless a force acts; more force means more acceleration; every push has an equal push back.

Example: A cyclist rides 30 m in 6 s. What is her speed? Speed = distance ÷ time. 30 ÷ 6 = 5. Answer: 5 m/s

Motion, Forces & Newton’s Laws in New York

In the New York State Learning Standards, this is unit 3 of 11 in 8th grade Science, after Cells & Life Processes and before Kinetic & Potential Energy.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    If the same force pushes a light cart and a heavy cart, which accelerates more?

    • the light cart
    • the heavy cart
    • both the same
    • neither

  2. Question 2

    What is a force?

    • a push or a pull
    • a mass
    • a speed
    • a kind of energy

  3. Question 3

    A cyclist travels 30 km in 2 hours. What is the average speed?

    • 60 km/h
    • 30 km/h
    • 15 km/h
    • 2 km/h

  4. Question 4

    Newton’s first law says an object at rest stays at rest unless…

    • it gets warm
    • an unbalanced force acts on it
    • it is looked at
    • it gets tired

  5. Question 5

    Why do passengers lurch forward when a bus stops suddenly?

    • the road pulls them
    • the seat pushes them
    • gravity turns off
    • their bodies keep moving because of inertia

  6. Question 6

    Why do seat belts and airbags protect people?

    • they stop gravity
    • they speed up the body
    • they spread out the force and slow the body gradually
    • they remove inertia

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