Question

An athlete completees one round of a circular track of diameter 200 m in 40 s . what will be the distance covered and the displacement at the end of 2 minutes 20 s ?​

Answer 1

Given :-

• Diameter of the circular track = 200m

       ∴ Radius of the circular track = 200/2

                                                        = 100m

• Time taken by athlete to complete one round = 40 seconds

       

To Find :-

• Distance covered at the end of 2 mins 20 secs.

• Displacement at the end of 2 mins secs.

Solution :-

→ 2 mins 20 secs = 2 × 60 + 20

                             = 120 + 20

                             = 140 secs

→ Distance covered in 40 secs = Circumference of circle

                                                   = 2πr

                                                   = 2 × π × 100

                                                   = 200π m

∴ Distance covered in one sec = 200π/40

                                                   = 5π m

Distance covered at the end of 2 min 20 sec :-

$\longrightarrow \sf 140 \times5 \times \pi \\\\\longrightarrow 140 \times 5 \times \dfrac{22}{7} \\\\\longrightarrow 20 \times 5 \times 22 \\\\\longrightarrow \bf 2200 \ m$

Displacement is the diameter of the circular track as it return to initial position again.

Displacement at the end of 2 min 20 sec :- 200m

Answer 2

Answer:

Given :-

• An athlete completes one round of a circular track of diameter 200 m in 40 s.

To Find :-

• How much distance covered and displacement at the end of 2 mins 20 secs.

Formula Used :-

❖ Speed = Distance ÷ Time ❖

✦ Circumference = 2πr ✦

Solution :-

Given :

• Diameter = 200 m
• Time taken = 40 seconds

First, we have to find the radius,

We know that,

➣ Radius = Diameter ÷ 2

⇒ Radius = 200 ÷ 2

➠ Radius = 100 m

Now,

➟ 2 mins 20 secs

↦ 2 × 60 + 20

↦ 120 + 40

➥ 140 secs

Then, number of round,

⇒ 140 ÷ 4

➣ 35

Now, we have to find distance covered,

⇒ Distance covered = 35 × 2πr

⇒ Distance covered = 35 × 2 × 22 ÷ 7 × 100

⇒ Distance covered = 70 × 22 ÷ 7 × 100

⇒ Distance covered = 220 × 100

➠ Distance covered = 22000 m

Hence, the distance covered at the end of 2 mins 20 secs is 22000 m .

And, the displacement at the end of 2 mins 20 secs is 200 m .