If an object is moving along a straight line and with respect to some reference point, its position is x₁ at time t₁ and becomes x₂ at time t₂ . The average velocity of the object during this time interval would be: 

The correct answer is (x2 - x1 ) / (t2 - t1 ).

Key Points

• The average velocity is defined as the total displacement divided by the total time taken.
• Mathematically, it is expressed as (x2 - x1) / (t2 - t1), where x1 and x2 are the initial and final positions, and t1 and t2 are the initial and final times respectively.
• This formula provides a measure of how fast an object is moving along a straight line over a specified time interval.
• Average velocity is a vector quantity, meaning it has both magnitude and direction.
• It differs from instantaneous velocity, which refers to the speed of an object at a particular moment in time.

Additional Information

• Displacement
  • It is the shortest distance between the initial and final positions of an object.
  • Displacement is a vector quantity, having both magnitude and direction.
  • It can be zero even if the distance traveled is non-zero, if the object returns to its starting point.
• Instantaneous Velocity
  • It refers to the velocity of an object at a particular instant of time.
  • Instantaneous velocity can be determined using differential calculus, by taking the derivative of the position function with respect to time.
  • Unlike average velocity, it provides the speed and direction of an object at a specific moment.
• Speed vs. Velocity
  • Speed is a scalar quantity that refers only to how fast an object is moving.
  • Velocity is a vector quantity that describes both the speed and direction of an object's movement.
  • Average speed is the total distance traveled divided by the total time taken, while average velocity is the total displacement divided by the total time taken.
• Uniform and Non-Uniform Motion
  • In uniform motion, an object travels equal distances in equal intervals of time.
  • In non-uniform motion, an object travels unequal distances in equal intervals of time.
  • For non-uniform motion, average velocity can provide an overall description of the motion over a time interval.