# Speed, Distance & Acceleration

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• speed, distance & acceleration
• Acceleration
• Acceleration is the change in velocity per second.
• Acceleration is measured in m/s2.
• a=v /t
• The triangle stands for “change in”.
• Speed
• Speed is measured in m/s.
• speed= distance/time
• Velocity
• Velocity is speed in a particular direction.
• Velocity is also measured in m/s.
• Distance-time graphs
• The ‘steepness’/gradient of the graph tells you the speed of the object.
• Steep line = high speed
• Less steep line = lower speed
• Flat/horizontal line = stationary
• Velocity-time graph
• The ‘steepness’/gradient of the graph tells you the acceleration.
• Steep line = high constant acceleration
• Less steep line = lower constant acceleration
• Flat/horizontal line = constant speed
• The area under the graph is the distance travelled.
• Stopping distance
• Stopping distance = Thinking distance + Braking distance
• Thinking distance: distance travelled between seeing the object and applying the brakes.
• Braking distance: distance travelled between applying the brakes and coming to a stop.
• Stopping distance: total distance travelled between seeing the object and stopping.
• thinking distance /    speed