Physics, asked by akshayag1120202021, 8 months ago

An athlete runs along a circular track of circumference 400m with a uniform speed 15m/s. What is the change in velocity when he runs through a distance of (i) 100m and (ii) 200m? ​

Answers

Answered by Anonymous
0

Answer:

The diameter of the circular track is given as 200 m. That is, 2r=200 m.

From this radius is calculated as Radius, r = 100 m.

In 40 sec the athlete complete one round. So, in 2 mins and 20 secs, that is, 140 sec the athlete will complete = 140 / 40 = 3.5 (three and a half) rounds.

One round is considered as the circumference of the circular track.

The distance covered in 140 sec = 2πr×3.5=2×3.14×100×3.5=2200 m.

For each complete round the displacement is zero. Therefore for 3 complete rounds, the displacement will be zero.

At the end of his motion, the athlete will be in the diametrically opposite position. That is, displacement = diameter = 200 m.

Hence, the distance covered is 2200 m and the displacement is 200 m.

Answered by sairam200612
1

Explanation:

Circumference of the track = 2*pi*r

= 2 * 3.14 * 100 m (as diameter is 200 m)

= 628 m

As the athlete covers one round in 40s, the speed of athlete,

S = Circumference/40s

Or, S = 628 m / 40 s

Or, S = 15.7 m/s ………. (1)

The distance covered by the athlete at the end of 2 min 20s (140 sec)

= 15.7 * 140 m

= 2198 m

So the distance covered = 2198 m

Now, 2198 m = 3* 628 + 0.5*628.

It means, the athlete has completed 3.5 rounds of the circular track at the end of 30 sec.

So, he/she is diametrically opposite of the starting point, at the end of 140 sec.

As, the displacement is the shortest distance between two points, in this case, it is 200 m (diameter).

So, Distance = 2198 m

Displacement - 200 m

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