Subscribe

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.

Maine Learning Results 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 Maine

In the Maine Learning Results, 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: Maine Department of Education

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

    A 2 kg object accelerates at 3 m/s². What force acts on it?

    • 1.5 N
    • 9 N
    • 6 N
    • 5 N

  2. Question 2

    What is inertia?

    • an object’s tendency to keep doing what it is doing
    • a kind of friction
    • a speed
    • a force

  3. Question 3

    When you push on a wall, the wall…

    • moves away
    • does not push
    • pushes back on you with the same force
    • pushes harder

  4. Question 4

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

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

  5. Question 5

    What is a force?

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

  6. Question 6

    On a distance-time graph, what does a flat horizontal line mean?

    • the object is moving fast
    • the object is speeding up
    • the object is not moving
    • the object is slowing

More 8th grade