Kinematics

High School

Definition

The branch of physics that describes motion—position, velocity, and acceleration—without considering the forces that cause it. Kinematic equations relate these quantities and allow the motion of objects to be predicted.

Worked examples

\(v = v_0 + at\)

This kinematic equation relates final velocity, initial velocity, acceleration, and time without needing force or mass.

A ball rolls at \(3 \, \)m/s\(\), then accelerates at \(2 \, \)m/s\(^2\) for \(4 \, \)s\(\). Final velocity: \(v = 3 + 2(4) = 11 \, \)m/s\(\).

Kinematics lets you predict the ball's speed using only motion quantities, ignoring what force caused the acceleration.

Common mistakes

Using kinematic equations when acceleration is not constant → Check that acceleration is constant before applying kinematic equations The standard kinematic equations only work for uniform (constant) acceleration.
Confusing kinematics with dynamics—trying to find motion without knowing acceleration or vice versa → Kinematics describes motion when you already know position, velocity, or acceleration values Kinematics assumes motion quantities are given; dynamics uses forces to find them.
Forgetting to assign correct signs to velocity and acceleration (direction matters) → Choose a positive direction and keep signs consistent throughout the problem Opposite-sign velocity and acceleration means slowing down; same sign means speeding up.

Where you'll use it next

You'll apply kinematics to solve projectile motion and free-fall problems, then combine it with Newton's laws in dynamics to analyze why objects move the way they do in mechanics and engineering.

Found in 1 StudyPug lesson

Mastering One-Dimensional Kinematic Equations

AS-Level Maths

Unlock the power of kinematic equations to analyze motion in one dimension. Learn to apply these fundamental tools to real-world scenarios and boost your physics problem-solving skills.

11th Grade11th