# P 2.1.1

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• Created by: Twins 1&2
• Created on: 19-12-13 10:44

## 1.1 Distance- Time graphs

- GRADIENT OF A LINE ON A DISTANCE-TIME GRAPH REPRESENTS SPEED.

- speed (m/s) = distance (m)/ time(s)

- On a graph:

Curved slope: acceleration

Straight slope: constant speed

Straight line: object is stationary

STEEPER THE LINE= FASTER THE SPEED

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## 1.2 Velocity and Acceleration

The velocity of an object is its speed in a given direction. If an object changes direction it changes velocity, even if its speed stays the same. If the velocity of an object changes we say it accelerates. We can calculate acceleration using the equation:                                                                                                                       A= the acceleration in metres per second, m/s²   , V= the final velocity, m/s                   U= the initial velocity, m/s   ,    T = the time taken for the change in seconds, s

If the value calculated for acceleration is negative, the body is decelerating, slowing down. A deceleration is the same as a negative acceleration.

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## 1.3 More about velocity-time graphs

Higher:  The area under the line on a velocity time-graph represents the distance travelled in a given time. The bigger the area, the greater the distance travelled.

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