Question

an athlet complete one round of a circular track of diameter 200 m in 40 second; what will be the distance covered and displacement at the end of 2 minute 20 second?​

Answer 1

Answer:

Distance in a circular track = circumference;

Circumference = 2PI r

Circumference = 2 x 3.142 [or] 22/7 x 200/2 [Radius = Diameter/2]

So, the circumference = 628.31m;

Irrespective of this all we did until now; let's find out the no.of rounds completed in 2min 20 secs.

So, to know the no.of rounds completed in 2 mins 20secs;

Let's first find out how many round will the athlet complete in 1 min;

So, As there is 40 secs+20 secs,So the athlete will complete 1.5 rounds in 1 min. Then for 2 min, It would be 1.5 x 2 rounds;

= 3 rounds in 2 mins;

Then as you know that for 20 mins, 0.5 round;

So, it will be 3 rounds + 0.5 round;

= 3.5 rounds;

Okay, so what is the distance covered by the object?

Well, Distance = Time x Speed;

Distance = 120 secs + 20 secs x 40

Distance = 140 x 40

Distance = 5600m,[ The circumference  of the round is irrespective, but you can use it if you want to. ]

Okay so the first part of the problem is done;

Displacement is 0 when the covered distance is replaced;

So, as this athlete travelled  it  3.5 rounds,

So he replaced the distance once, again displaced it, and again replaced half of the round;

So, Half of the round = 628.31m x 1/2;

= PI [22/7] is the constant and the exact answer of the displacement!

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