During a practice session in a stadium, an athlete runs along a circular track and her performance is observed by her coach standing at a point on the circle and also by her physiotherapist standing at the center of the circle. The coach finds that she covers an angle of 72° in 1 min. what will be the angle covered by her in 2 seconds according to the measurement made by her physiotherapist?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 4.8°.
The angle subtended by the arc at the center is double the angle subtended by the same arc at the circumference of the circle.
Suppose the athlete runs from point P to Q in 1 minute and the coach and the physiotherapist observe him from points R and S respectively.
Given, ∠PSQ = 72°
Then,
⇒ ∠PSQ = 2 × 72 = 144°
Hence, according to physiotherapist the athlete covers an angle of 144° per minute
∴ In 1 second, the angle covered by the athlete according to physiotherapist = 144/60 = 2.4°
For 2 seconds, the angle covered by the athlete according to the physiotherapist = 2.4° × 2 = 4.8°