Question

An athlete, running on a circular track of radius 700 m, reaches the exact opposite end from where he started, in 30 s. What will be his displacement from the starting position​

Answer 1

Given :

• An athlete, running on a circular track of radius 700 m, reached on the opposite end from where he started running.
• Time (t) = 30 s

To Find :

• Displacement of the athlete

Solution :

As we're given that the athlete is running around a circular track and it covers half distance of the circle. as we know that circumference of circle is given by :

⇒Circumference = 2πr

And also it travels to the opposite end from where it starts means, he travelled distance of half of the circumference of the track

⇒Distance = 2πr/2

⇒Distance = πr

⇒Distance = (3.14) * 700

⇒Distance = 2198

⇒Distance ≈ 2200 m

$\therefore$ Distance travelled by athlete is 2200 m or 2.2 km

_________________________________

As we know that displacement is the shortest path taken by body to travel same distance. So, if the athlete moves from the centre of the circle he have to travel displacement of the diameter of track. and which is the shortest path.

⇒Displacement = Diameter

⇒Displacement = 2r

⇒Displacement = 2(700)

⇒Displacement = 1400 m

$\therefore$ Displacement travelled by athlete is 1400 m