Object B travels 4m in 10s. It is slower so its graph is less steep.
We can use the equation Speed = distance / time to calculate the speed of each object.
B has a speed of 10 / 4 = 2.5 m/s
Remember: STEEPER = FASTER
Describing Motion
Even when things are moving in a straight line, describing their movement is not easy. They can move with different speeds and can also change their speed and/or direction (accelerate). Graphs can help us to describe the movement of the body. These may be distance-time graphs or velocity-time (speed-time) graphs.
This is a distance time graph. It tells us what distance an object has travelled at certain times.
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Object A travels 5m in 4s then stops.
Object B travels 4m in 10s. It is slower so its graph is less steep. We can use the equation Speed = distance / time to calculate the speed of each object. B has a speed of 10 / 4 = 2.5 m/s Remember: STEEPER = FASTER |
This is a speed time graph. It tells us how fast something is travelling at different times.
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Object C accelerates from rest reaching a speed of 30 m/s in 6 seconds Object D accelerates from rest reaching a speed of 10 m/s in 4 seconds. It travels at 4 m/s for 4 seconds then slows and stops in 2 seconds. We can use the equation Acceleration = change in speed / time to calculate the acceleration of an object. C has an acceleration of 30 / 6 = 5 m/s2 Remember: STEEPER = BIGGER ACCELERATION |
We can also find how far an object has travelled from a speed time graph by finding the area
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