Question

The first half of total distance of 50 km is covered in 2 h, and the second half in 3 h. The average speed is ______.

• A. 13.8 ms^-1
• B. 7 ms^-1
• C. 2.78 ms^-1
• D. 5.56ms^-1

Answer 1

The correct option is C 2.78 ms^-1

Given:
The total distance, d= 50km
Total time, T = 2h+3h = 5h
Average speed = d/t = 50km/5h
→ Vavg = 10kmph
also 1km = 1000m,
1h = 60min = 3600s
→ 10kmph = 10 × 1000/3600 ms^-1
= 25/9 ms-1 = 2.78 ms^-1
؞ Average speed = 2.78ms^-1