1.1 Distance-Time graphs
- Gradient of the line on a distance-time graph represents an object's SPEED.
- The STEEPER the line the GREATER the speed it represents
- Equation: Speed in metres per second, m/s =
distance travelled in metres,m (divide) time taken in seconds,s
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1.2 Velocity and Acceleration
- VELOCITY is SPEED in a given DIRECTION.
- If and object changes direction it also changes Velocity even if the speed is still the same.
- If the Velocity changes then we say that it ACCELERATES.
- ACCELERATION is the change of velocity per second.
- DECELERATION is the same as negative acceleration
- Equation: a = v - u
- Symbols and meanings:
- a is acceleration in metres per second,m/s²
- v is the final velocity (The velocity we have at the end) in metres per second, m/s
- u is the initial velocity (starting velocity) in metres per second, m/s
- t is the time taken for the change (Make sure to convert from hours to seconds) in seconds,s
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1.3 More about Velocity-Time Graphs
- If the line on a velocty-time graph is HORIZONTAL, the acceleration is ZERO therefore the object is travelling at a steady speed.
- The GRADIENT represents acceleration.
- The area under the velocity-time graph is the DISTANCE travelled.(HIGHER)
- If the gradient of the line is NEGATIVE the object is decelerating.
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1.4 Using Graphs (HIGHER)
- The SPEED of an object is given by the GRADIENT of the line on its DISTANCE-TIME graph
- The ACCELERATION of an object is given by the GRADIENT of the line on its VELOCITY-TIME graph.
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