Question

A car travel at 54 km/h for first 20s, 36km/h for next 30s and finally 18km/hfor next 10s. find the average speed.​

Answer 1

Answer:

I think 36km/h is correct average speed

Explanation:

May it is help you

Answer 2

Answer:

10.83m/s

Explanation:

54 km/hr = 54 x 5/18 = 15 m/s

36 km/hr = 36 x 5/18 = 10 m/s

18 km/hr = 18 x 5/18 = 5 m/s

1st Case ---

Speed = 15m/s

Time = 20 s

Distance = Speed x Time = 15 x 20 = 300 m

2nd Case ---

Speed = 10 m/s

Time = 30 sec

Distance = 10 x 30 = 300 m

3rd Case ---

Speed = 5 m/s

Time = 10s

Distance = 5 x 10 = 50 m

Now Total Distance = 300 + 300 + 50 = 650 m

Total time = 20 + 30 + 10 = 60 s

Average Speed = 650/60 = 65/6 m/s=10.83m/s

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Hope this will help you :)

Physics

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