question_answer

The ADCL IIT Foundation conference theatre of a school is 15 m wide and has a door at a comer. A teacher enters at 8.00 am through the door and makes 10 rounds along the 15 m wall back and forth during the period and finally leaves the class-room at 9.30 a.m. through the same door. Compute his average speed and average velocity.

Answer:

(i) IIT Foundation School width = 15m, the number rounds made by a teacher along the width 15m = 10 (i.e. even) the time period for the above duration = 9.30 - 8.00 = 90 min. \[Average\text{ }speed=\frac{Total\text{ }distance\text{ }travelled}{Total\text{ }time\text{ }taken}\] \[=\frac{15\times 10}{90}=(5/3)m/\min \] (ii) Since teacher made even rounds, his final position is equal to the initial position. hence displacement of a teacher is zero. \[\therefore \]average velocity of a teacher is zero.