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Bodies in Motion
When considering the motion of a body we often need to know details of its speed and the distance it has travelled. In some cases the nature of the motion is very complex and there is no alternative to an in-depth mathematical analysis or experimental measurement.
There are however many cases in which the motion is fairly simple, or can be approximated to a simple analysis. The equations below are for a body subject to a constant rate of acceleration (or deceleration)
v = u + a t
s = ( u + v ) t / 2
s = u t + 0.5 a t2
v2 = u2 + 2 a s
p = m v
E = 0.5 m v2
| Symbol | Units | |
| u | Initial speed in metres per second | m s-1 |
| v | Final speed in metres per second | m s-1 |
| a | Acceleration (Deceleration if negative) in metres per second per second | m s-2 |
| t | Time in seconds | s |
| s | Distance in metres | m |
| m | Mass in kilograms | kg |
| p | Momentum in kilogram metres per second | kg m s-1 |
| E | Kinetic energy in Joules | J |