Question

A person travels around a circular path of radius 21 m. After traveling half a revolution in 10s, he stops. Calculate the distance, displacement and the average speed of the person

Answer 1

Answer:

I think this is the correct explanation of this question

Answer 2

Answer:

$\rightarrow$ Distance = 66 m

$\rightarrow$ Displacement = 42 m.

$\rightarrow$ Average Speed = 6.6 m/s.

Explanation:

Given -

• Radius = 21 m
• Time = 10 secs.

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To Find-

• Distance.
• Displacement.
• Average speed.

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Solution-

$\blue\bigstar$Distance -

Distance here will be the half of the circumference of the circle = 2×$\frac{22}{7}$×radius÷2

=$\frac{22}{7} \times 21 \times 2 \times \frac{1}{2} \\ \\ = 22 \times 3 \\ \\ = 66 \: m$

Distance is 66 m.

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$\pink\bigstar$Displacement-

Displacement refers to the shortest distance between the initial and the fin points, so, here, the displacement would be twice of its radius = 2×21= 42 m

Displacement is 42 m.

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$\purple\bigstar$Average Speed -

Distance = 66 m.

Time = 10 secs.

Average speed refer to total distance upon total time.

$\tt\red{Average\:speed=\frac{total\:distance}{total \:time}}$

$= \frac{66}{10} \\ \\ = 6.6$

Average speed is 6.6m/s.