Question

A man is walking on a circular path of radius 7 m. He starts from A and reaches B in 10 s and then comes back to A along the diameter of the circular track in 2 s. What is his average speed for the journey?

• A. 1 m/s
• B. 3 m/s
• C. 0 m/s
• D. 7 m/s

Answer 1

The correct option is B 3 m/s

Distance travelled from A to B along the circular track,
$d_1$ = Circumference of the semicircle
= $\pi r=\frac{22}{7}\times 7$ = 22 m

Distance travelled from B to A along the diameter, $d_2$ = 2r = 14 m

Total distance, $d_1$+ $d_2$ =22 + 14 = 36 m
Total time, T = 10 + 2 = 12 s
$\text{Average speed,}{v}_{av}=\frac{36}{12}=3m/s$