Physics

Kinematics Equations

Kinematics describes motion without worrying about forces. For uniformly accelerated motion (constant a), four equations relate displacement, initial/final velocity, acceleration, and time.

How to Approach Kinematics Equations

1

List what you know and what you need

Write down the known quantities (initial velocity v₀, acceleration a, time t, etc.) and circle the one you're solving for.

2

Pick the right kinematic equation

Use the equation that contains your knowns and your target. The four are: v = v₀ + at, x = v₀t + ½at², v² = v₀² + 2ax, x = ½(v + v₀)t.

3

Solve & check units

Plug in numbers, solve algebraically, then check that the units work out. Distance should come out in meters, velocity in m/s.

Frequently Asked Questions

What does 'uniform acceleration' mean?+

Acceleration is constant — its magnitude and direction don't change. Falling under gravity (g = 9.81 m/s²) is uniform acceleration.

How do I handle 2D motion?+

Treat horizontal and vertical components separately. Each axis has its own kinematic equations; time is the common link between them.

What's a freely falling object's acceleration?+

On Earth, near the surface, ≈ 9.81 m/s² downward, ignoring air resistance. This is the special case of kinematics with a = g.

Related Topics

More step-by-step guides in Physics and adjacent subjects.

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