2.6 Equations of Motion

There are three basic equations of motion for bodies moving with uniform acceleration:

First Equation of Motion

v = vi + at

Second Equation of Motion

S = vit + ½at²

Third Equation of Motion

v² = vi² + 2aS

Example Problems

Example 2.11

A train slows down from 80 km/h with a uniform retardation of 2 m/s². Time to reach 20 km/h: 8.3 s

Example 2.12

A bicycle accelerates at 1 m/s² from 4 m/s for 10 s. Distance moved: 90 m

Example 2.13

A car accelerates from 5 m/s to 15 m/s over 50 m. Acceleration: 2 m/s², Time: 5 s