Question

5. A car travels half of the distance with constant velocity 40 km/h and another half with a constant velocity of
60 km/h along a straight line. The average velocity of the car is
(1) 24 km/h
(3) 60 km/h
(2) 48 km/h
(4) 40 km/h

(class 11 motion in a straight line )​

Answer 1

Explanation:

ans will be 48km/hr as the time varies

Answer 2

Answer:

48km/hr

Explanation:

Given :

A car travel half of the distance  with constant velocity of 40km/hr and another half with a constant velocity of 60km/hr.

To Find :

Average velocity = ?

Solution :

We know,

$\sf{}Average\ velocity =\dfrac{Total\ Distance}{Total\ Time}$

Let the distance be “s”

We know,

$\sf{}Speed =\dfrac{Distance}{Time}$

So,

$\sf{}Time =\dfrac{Distance}{Speed}$

Time taken to cover half of the distance = s/40 hr

Time taken to cover the other half = s/60 hr

Therefore,

$\sf{}Average\ velocity =\dfrac{Total\ Distance}{Total\ Time}$

$\sf{}\implies \dfrac{s+s}{\frac{s}{40}+\frac{s}{60}}$

$\sf{}\implies \dfrac{2s}{\frac{s}{40}+\frac{s}{60}}$

$\sf{}\implies \dfrac{2s}{\frac{s\times 3+s\times 2 }{120}}$

$\sf{}\implies 2s\div \dfrac{5s}{120}$

$\sf{}\implies 2s\times \dfrac{120}{5s}$

$\sf{}\implies 2\times \dfrac{24}{1}$

$\sf{}\sf{}\therefore 48km/hr$

Therefore average velocity is equal to 48km/hr