Question

A car travels from A to B at 60 km/h and returns to A at 90 km/h .what is it's average velocity and average speed?

Answer 1

Average Velocity = 0 km/h as displacement becomes 0 km.

Average Speed:-

Since Distances Travelled are equal

there V(av)= 2v1v2/v1+v2

=2x60x90/60+90

10800/150

=72km/h

Answer 2

The average speed and average velocity are 72km/h and 75km/h.

Given:

A car travels from A to B at 60km/h and returns to A at 90km/h.

To Find:

The average velocity and average speed.

Solution:

Here, the distance was taken by the car from the point $Ato B=60km/h$.

and returns to $A$ at $90km/h$.

Now, by the applying the formula of average speed $=\frac{2(S_1\times S_2)}{S_1+S_2}$

after putting the given values in the above formula.

we get,

Average speed,

$=\frac{2(60\times 90)}{60+90} \\=\frac{10800}{150} \\=72km/h$

Now, the initial velocity $(u)=60km/h.$

and the final velocity $(v)=90km/h$.

so, the average velocity $=\frac{v+u}{2}$.

now, by putting the given values in the above formula.

we get,

Average velocity,

$=\frac{60+90}{2} \\=\frac{150}{2} \\=75km/h.$

Hence, the average speed and average velocity are 72km/h and 75km/h.

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