Physics

Third Equation of Motion

Relate velocity, acceleration and displacement without time.

v² = u² + 2as

Formula Explanation

This equation applies to straight-line motion with constant acceleration.

Variables Explained

u = Initial velocity; v = Final velocity; a = Acceleration; s = Displacement.

Solved Example

An object starts from rest and accelerates at 4 m/s² over 8 m.
v² = 0 + 2 × 4 × 8 = 64; v = 8 m/s.

Exam Tip

Choose the positive or negative root according to the physical situation.