Question

Find the average speed of a bicycle if it completes two round of a circular track of radius

140m twice in 5min 52 sec.

(a) 10m/s

(b) 5m/s

(c) 2m/s

(d) 4m/s​

Answer 1

Answer:

5 m/s

Explanation:

Given:

• Radius of the circular track = 140 metres (r)
• Time taken = 5 minutes 52 seconds
• Two rounds were completed

To find:

• Average speed

Average speed = $\frac{Total \ distance}{Total \ time}$

Total distance = $2 \times 2\pi r$ (As two rounds were completed)

Total distance = $2 \times 2 \times \frac{22}{7} \times 140$

Total distance = 1760 metres

Total time = 5 minutes 52 seconds

1 minute = 60 seconds

5 minutes 52 seconds = $5 \times 60 +52$

5 minutes 52 seconds = 352 seconds

Average speed = $\frac{1760}{352}$

Average speed = 5 m/s

The average speed of the bicycle is equal to 5 m/s

Answer 2

Answer:

Given –

• Radius of the circular track = 140 m.
• Time taken = 5 minutes 52 seconds.
• Two rounds were travelled.

To Find –

• Average speed

Solution –

We know that, Average speed = Total Distance/Total Time.

Total Distance = 2*2πr

➸ 4 * 3.14 * 140

➸ 12.56 * 140

➸ 1758.4 m

Total Time = 5 min 52 sec

➸ 5*60 + 52

➸ 300 + 52

➸ 352 seconds

Hence, Average speed = 1758.4/352

Average speed of the bicycle = 4.995 that is approximately 5 m/s.