Velocity and Acceleration
Velocity is speed in a particular direction.
Acceleration is the change in velocity.
Acceleration is typically given in meters per second per second (m/s2). In each second a velocity gets faster by so many meters per second.
- Acceleration is often described in gs.
- Uniform velocity is when the velocity stays the same.
It can be worked out simply by dividing the distance traveled (d) by the time (t): u=d/t.
- Positive acceleration is getting faster; negative acceleration, or deceleration, is getting slower.
- A rifle bullet accelerates down the barrel at 3000 m/s2. A fast car accelerates at 6 m/s2.
- When an object falls, the Earth’s gravity makes it accelerates at 9.81 m/s2. This is called g.
- In a rocket taking off at 1 g, the acceleration has little effect, but at 3 g, it is impossible to move your arms and legs; at 4-5 g you black out in five seconds.