What are some other important speeds to remember?

Other important speeds to remember are: Car on a main road – 13m/s Fast train in the UK – 50m/s Cruising aeroplane – 250m/s And Speed of sound in air – 330m/s Although the sound of speed can vary e.g. sound travels faster on warmer days than on cooler ones. And the speed of a moving object is rarely constant as a car will speed up and slow down over a journey, but average speeds are used to make calculations easier.