Acceleration - D velocity

    Increasing in velocity --- Positive acceleration
    Decreasing in velocity --- Negative acceleration
     Change in direction --- Circular motion
 

                            Based on definition
 
                                Define velocity
                                    Speed in a certain direction

 
 
  Look at the cars in the box.  Describe their motion.  Which one has constant speed?    Which one accelerates slowly?  Which one accelerates quickly?
 
 
 Look at the velocity arrow as the ball moves around the corner.
    Although the speed does not change, the velocity does because the direction changes therefore the ball has acceleration.

The Rule of Thumb is explaining the arrow on the ball representing acceleration.
    The arrow is representing a negative acceleration when it facing the opposition direction of the motion of the ball.
 

 

Negative acceleration (deceleration or slowing down)  can be expressed in a couple of ways.  The actually speed for each second... or  the amount the speed from the origninal that has been lost.

 
 Calculating Acceleration when speed changes