Why Mechanics Matters
Mechanics is the backbone of physics. In JAMB, it typically accounts for 30–35% of questions. Get this right and you're already in A grade territory.
Kinematics: The Equations of Motion
These four equations describe motion under constant acceleration:
- v = u + at
- s = ut + ½at²
- v² = u² + 2as
- s = ½(u + v)t
Where: u = initial velocity, v = final velocity, a = acceleration, t = time, s = displacement
Newton's Three Laws
First Law (Inertia): An object remains at rest or in uniform motion unless acted upon by a net external force.
Second Law: F = ma. Force equals mass times acceleration. This is the most used equation in mechanics.
Third Law: For every action, there is an equal and opposite reaction.
Work, Energy & Power
- Work: W = Fd cos θ (force times displacement times cosine of angle between them)
- Kinetic Energy: KE = ½mv²
- Potential Energy: PE = mgh
- Power: P = W/t = Fv
Projectile Motion
When an object is launched at an angle, it follows a parabolic path. Key facts:
- Horizontal and vertical motions are independent
- Horizontal velocity is constant (no air resistance)
- Vertical motion is affected by gravity (g = 10 m/s²)
- Maximum range is achieved at 45°
JAMB Strategy
- Always write out what's given before attempting calculations
- Draw diagrams for force problems — it clarifies everything
- Memorize g = 10 m/s² for JAMB (some textbooks use 9.8, but JAMB uses 10)
- Check units in your final answer