?A boy is running over a circular track with uniform speed of 10m/s . ...
Explanation:
Definitions:
Speed: The distance travelled by an object per unit time is called its speed.
Velocity: The displacement of an object per unit time is called its velocity.
Average Velocity: The total displacement of an object divided by the total time taken is called its average velocity.
Formula:
Average Velocity = Total Displacement / Total Time Taken
Calculation:
Given, the boy is running over a circular track with uniform speed of 10m/s.
To find the average velocity for movement of boy from A to B, we need to find the total displacement and total time taken by the boy.
Finding Total Displacement:
The track is circular. So, the boy will complete one lap of the track to come back to point A.
Let the radius of the circular track be 'r'.
Length of the circular track = Circumference of the circle = 2πr
Distance travelled by the boy to complete one lap = Length of the circular track = 2πr
Distance travelled by the boy from A to B = Half of the length of the circular track = πr
As the boy moves from A to B, his displacement is equal to the distance between A and B.
Displacement from A to B = πr (as the displacement is in a straight line)
Finding Total Time Taken:
As the boy is running with a uniform speed of 10m/s, the time taken to complete one lap of the track is equal to the length of the track divided by the speed of the boy.
Time taken by the boy to complete one lap = Length of the circular track / Speed of the boy
Time taken by the boy to complete one lap = (2πr) / 10
Time taken by the boy to complete one lap = (πr) / 5
Time taken by the boy to move from A to B = Half of the time taken to complete one lap = (πr) / 10
Finding Average Velocity:
Average Velocity = Total Displacement / Total Time Taken
Average Velocity = (πr) / [(πr) / 10]
Average Velocity = 10m/s
Conclusion:
Therefore, the average velocity for the movement of the boy from A to B is 10m/s.