The resultant force acting on an object can cause objects to accelerate or decelerate.

resultant force = mass x acceleration

(newton, N) (kilogram, kg) (metres per second^{2}, m/s^{2})

**distance-time graphs**

The gradient of a distance-time graph represents the speed of the object.

Graph for stationary object.

Graph for a slow moving object (small gradient).

Graph for a fast moving object (steep gradient).

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**Velocity & Speed**

**Speed** example = **5 m/s**

**Velocity** example = **5 m/s North**

A speed only has a size like 20 m/s but a speed in a particular direction like 20 m/s left is called a velocity.

**Acceleration**

The acceleration of an object is measured in metres/second^{2} ( m/s^{2}).

acceleration = change in velocity

time taken for change

**velocity-time graphs**

Graph for object moving a constant velocity.

Graph for object accelerating.

Graph for an object decelerating.

**Acceleration for a velocity-time graph**

Finding the gradient of a velocity-time graph gives you the acceleration of the object. The greater the gradient the greater the acceleration.

**Distance travelled from a velocity-time graph**

The distance travelled by an object can be found from the area underneath a velocity-time graph.

The area underneath this graph is a triangle.

The area of a triangle = 0.5 x base x height = 0.5 x 10 x 5 = 25m.

The distance travelled by the object is 25m.