An athlete completes one round of a circular track ofradius R in 40 seconds. The displacement at the endof 2 minutes 20 seconds isa)0b)2Rc)d)Correct answer is option 'B'. Can you explain this answer?

Question

Answer

2 minutes 20 seconds=140 seconds or 40+40+40+40/2 seconds One round takes 40 second so it is clear that 3 and1/2 rounds are done. after three round final and initial status are same after 1/2 more round athlete completes half of the circle So final and inial status are on the edges of diameter. Displacement is diatance between final and initial status So it is equal to diameter or 2R.

Answer

In 40 sec, no. of round completed = 1 = 2πr In 1 sec, no . of round completed = 1/40 = 2πr/40 therefore in 2 min 20 sec i.e. 140 sec, no of round completed = 140×1/40 = 3.5 complete round means 3 complete round which gives displacement zero but in 0.5 left round the athlete which opposite side of the circle i.e. diametrically opposite side so his net displacement is 2R therefore (b) is correct

Answer

How to solve?

Answer

B

Answer

There is circular track so we should take pie as well

Answer

Explanation:
The athlete completes one round of the circular track in 40 seconds, which means he travels a distance equal to the circumference of the circle, i.e., 2πR.

Calculating Displacement:
1 minute and 20 seconds is equivalent to 80 seconds. In 80 seconds, the athlete completes 2 rounds of the track. Therefore, his total displacement at the end of 2 minutes and 20 seconds is equal to the diameter of the circle.

Displacement Formula:
The displacement of an object moving in a circle is given by the diameter of the circle.

Final Displacement:
Therefore, the displacement of the athlete at the end of 2 minutes and 20 seconds is 2R.

Conclusion:
The correct answer is option 'B' (2R), as the athlete's displacement at the end of 2 minutes and 20 seconds is equal to the diameter of the circular track.

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