Question

A man walks with a speed of 6km/h for 1km and 8km/h for next 1km. Calculate his average speed for the whole journey in (m/sec).​

Answer 1

Explanation:

8 + 6 = 14km/h

km/h = 1000/3600 = 5/18

14 × 5/18 m/s

35/9 m/s

Answer 2

Given :

▪ A man covers first 1km with a speed of 6kmph and another 1km with a speed of 8kmph.

To Find :

▪ Average speed of man.

Concept :

☞ Average speed is defined as the ratio of total distance travelled to the total time taken.

☞ It is a scalar quantity.

☞ It has only magnitude

☞ It can't be negative or zero.

☞ SI unit : m/s

Calculation :

→ Vav = (d1 + d2) / (t1 + t2)

→ Vav = (d1 + d2) / [(d1/v1 + d2/v2)]

→ Vav = (1 + 1) / [(1/6) + (1/8)]

→ Vav = 2 / (14/48)

→ Vav = 2×48 / 14

→ Vav = 6.85kmph

↗ 1kmph = 1000/3600 = 5/18mps

Therefore, 6.85kmph = 6.85×5/18

❇ Vav = 1.9 mps