A cyclist starts from the centre O of a circular track of radius r = 1 km, reaches the edge P of the track and then cycles along circumference and stops at point Q. if the total time take is 10 min, what is the average velocity of the cyclist?
6 km h–1
The displacement of the cyclist in moving from P to Q along the circumference = shortest distance between P and Q = straight line distance PQ in the direction from P to Q. The net displacement in moving from O to P and then from P to Q = resultant of vector displacement OP and PQ. From the triangle law of vector addition, the magnitude of the net displacement = OQ = 1 km. Now, the time take = 10 min Therefore, average velocity is 1 km/ = 6 km h–1.
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