In a running event the rate at which the velocity changes with respect to time is known as

Explanation:

• Velocity: 
  • the rate of change of the object's position with respect to a frame of reference and time
• Deceleration: 
  • The Deceleration can be calculated by dividing the final Velocity minus the initial Velocity, by the amount of time taken for this drop in Velocity.
• Speed: 
  • The rate of change of position of an object in any direction. 
  • Speed is measured as the ratio of distance to the time
• Acceleration: 
  • Acceleration is the name we give to any process where the velocity changes.
  • Acceleration is the rate of change in velocity with time.

Thus, in a running event the rate at which the velocity changes with respect to time is known as acceleration.