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8th grade · Science · Unit 2 of 7

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.

Alaska content 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 Alaska

In the Alaska content standards, this is unit 2 of 7 in 8th grade Science, after Light & Radiation 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: Alaska Department of Education and Early Development

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

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

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

  2. Question 2

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

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

  3. Question 3

    Newton’s second law says that force equals…

    • mass × acceleration
    • mass + speed
    • speed ÷ time
    • distance × time

  4. Question 4

    What is gravity?

    • a type of speed
    • a force that pushes objects apart
    • a light
    • a force that pulls objects toward each other

  5. Question 5

    What is friction?

    • a kind of gravity
    • a force that opposes motion between touching surfaces
    • a force that speeds things up
    • a kind of magnetism

  6. Question 6

    What makes an object more stable?

    • a tall shape
    • a high center of mass
    • a low center of mass and a wide base
    • a narrow base

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