Speed
Science: KS3, topic 3.2.10
Speed
Speed is the rate of movement or how fast something is moving.
Speed
- Speed is the rate of movement of an object.
- High-speed trains cover more distance in a shorter space of time.
- Snails move at low speeds because they only cover short distances in a long time.
- Objects that are not moving have no speed.
- If you are standing still on the equator, you will be spinning over 1,000 miles per hour as well as traveling around the Sun at around 67,000 miles per hour.
Speed calculation
- Speed is calculated by:
- Average speed = distance ÷ time.
- If speed is measured in meters per second (m/s):
- Distance would be in metres (m) and time in seconds (s).
- If speed is measured in kilometres per hour (km/h):
- Distance would be in kilometres (km) and time in hours (h).
- If speed is measured in miles per hour (mph):
- Distance would be in miles and time in hours (h).
Average speed
- We calculate average speed because speed may change throughout the time an object is in motion.
- For instance, if a car speeds up at some traffic lights and then stops, speed will increase and then decrease.
- A car traveling 500m in 10s has an average speed of:
- 500 ÷ 10 = 50m/s.
Test yourself on Speed
Why do we use the term average speed?
Which of these is true of speed?
Which of these is true about speed?