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?

Answer 1

Answer:

i don't know the answer of this question

Answer 2

Answer:

The average speed of the car between A and D is 17.14m/s

Explanation:

Given that,

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.

Also given, the time taken in the mentioned sections is 20s, 10s and 5s respectively

We are required to find the average speed of the car between points A and D.

The distance covered between points A and B is $d_{AB}=v_{AB}t_{AB}=20\times20=400m$

The distance covered between points B and C is

$d_{BC}=v_{BC}t_{BC}=15\times10=150m$

The distance covered between points C and D is

$d_{CD}=v_{CD}t_{CD}=10\times5=50m$

Now the average speed for the entire journey is the ratio of total distance to the total time taken.Therefore,

$V_{avg}=\frac{400+150+50}{20+10+5} =\frac{600m}{35s} =17.14m/s$

Therefore,the average speed of the car between A and D is 17.14m/s

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