Question

Average speed of a car between points A and B is 20 m/s, between B and C is 15 m/s, between C and D is 10 m/s. What is the average speed between A and D, if the time taken in the mentioned sections is 20s, 10s and 5s respectively?

• A. 17.14 m/s
• B. 15 m/s
• C. 10 m/s
• D. 45 m/s

Answer 1

Answer:

A. 17.14 m/s

Average speed is the total distance divided by total time taken. Total displacement (d = vt) = 20×20 + 15×10 + 10×5 = 600 m. Total time = 20 + 10 + 5 = 35 s. Therefore, average speed = 600/35 = 17.14 m/s.