Question

A particle moves for the first one third of the total time of journey with speed 30 kilometre per hour and with speed 15 kilometre per hour for remaining time average speed during total journey is

Answer 1

Answer:

20 km per hour

Explanation:

let  full distance D and total taken time i s T

THE RATIO OF D AND T GIVE US AVERAGE SPEED

NOW according to que.  (T/3)*30  + (2T/3)*15 = D

AFTER SOLVING THIS EQUATION EW GET D/T RATIO =20

Answer 2

Given :

Speed of particle in first one third of the total time is , u = 30 km/h .

Speed of particle in rest of time , v = 15 km/h .

To Find :

The average speed of total journey .

Solution :

Let , total time be t .

Now , we know , average velocity is given by :

$v_{avg}=\dfrac{Total \ distance }{Total\ time\ taken}\\\\v_{avg}=\dfrac{30 \times \dfrac{t}{3}+15 \times \dfrac{2t}{3} }{t}\\\\v_{avg}=20\ m/s$

Therefore , average speed during total journey is 20 m/s .

Learn More :

Kinematics

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