Study of motion
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15. Acceleration

From rest, a rally car can reach a velocity of 100 km/h in 2,5 s or less. It gains velocity very rapidly. It has a high acceleration.

Like velocity, acceleration has a direction, it is a vector quantity.

Acceleration is calculated as follows:
Figure 8.8


An object is said to be accelerating if it is :

- Speeding up
- Slowing down
- Changing direction
- Speeding up and changing direction
- Slowing down and changing direction

Acceleration can be positive or negative. If a car has an acceleration of -4 m/s2, it is losing 4 m/s of speed every second. A negative acceleration is sometimes called deceleration.


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