DepEd MELC reviewer for Grade 8 Science, Quarter 1. Master the concepts, tables, and common-mistake warnings below.
1
Newton's Three Laws of Motion
| Law | Statement |
|---|---|
| 1st (Inertia) | Objects keep their state unless a force acts |
| 2nd | F = m × a (force = mass × acceleration) |
| 3rd | Every action has an equal and opposite reaction |
F = m × a
2
Work and Power
Work = Force × distance (W = Fd) | Power = Work ÷ time
⚠️ Common Mistake
If an object does NOT move, no work is done — even if you push hard. Work needs motion in the force’s direction.
3
Energy
Kinetic energy = energy of motion; potential energy = stored energy due to position. Energy is conserved — it transforms, never disappears.
4
Worked Example
A 2 kg ball accelerates at 3 m/s². Find the force.
F = m × a = 2 × 3 = 6 N
Force is measured in newtons (N).
📌 Quick Recap — Master These
Before your test, make sure you can confidently do each of the following:
- Explain and apply Newton's Three Laws of Motion.
- Explain and apply Work and Power.
- Explain and apply Energy.
- Explain and apply Worked Example.
Re-read any section above where you hesitate, then try the worked example again without looking.