Question

An athlete runs on a circular track of diameter 200m. He completes 1 round in 60 seconds. Calculate his distance and displacement at the end of 150 sec

Answer 1

Diameter = 2 × Radius = 200m

Therefore, radius = 100m

1 Round = Circumference = 2πr= 4400/7= 638.5m (approx)

A.T.Q. 1 ROUND IN 60 SECONDS

THEREFORE IN 1 SECOND 1/60 ROUNDS.

IN 150 seconds (1/60×150) rounds

= 2.5 Rounds

Thus, In 150 seconds DISTANCE travelled = (2.5×638.5)m

= 1596.25m

ALSO , DISPLACEMENT = 2.5 ROUNDS - 2 ROUNDS {SINCE DISPLACEMENT AFTER 1 ROUND IS ZERO}

THUS , DISPLACEMENT = 0.5× 638.5

DISPLACEMENT = 319.25m