Question

a car moving along straight moves with the speed of 40 km/ h for one hour during next hour car moves with speed of 60 kmh determine it's Average speed.​

Answer 1

Answer:

Explanation:Average speed=2xy/x+y

Average speed=2(40)(60)/40+60

=4800/100=48kmph

Answer 2

Given:

Speed of car for first hour,v₁= 40 km/h

Speed of car for second hour,v₂= 60 km/h

To Find:

Average speed of car

Solution:

We know that,

• Average speed of a body S is given by

$\pink{\boxed{\bf{S=\dfrac{Total\ distance\ covered}{Total\ time\ taken}}}}$

• $\pink{\boxed{\bf{Distance=Speed\times Time}}}$

$\rule{190}{1}$

Let the time taken by car while travelling 40 km/h be t₁ and Let the time taken by car while travelling 60 km/h be t₂

Here,

$\longrightarrow\rm{t_{1}=1 h}$

$\longrightarrow\rm{t_{2}=1 h}$

Let the distance travelled be car in first hour be d and distance travelled by car in second hour be d'

So,

$\longrightarrow\rm{d=v_{1}t_{1}}$

$\longrightarrow\rm{d=40\times1}$

$\longrightarrow\rm{d=40\ km}$

Also

$\longrightarrow\rm{d'=v_{2}t_{2}}$

$\longrightarrow\rm{d'=60\times1}$

$\longrightarrow\rm{d'=60\ km}$

$\rule{190}{1}$

Now, let the average speed of car be S

So,

$\longrightarrow\rm{S=\dfrac{Total\ distance\ covered}{Total\ time\ taken}}$

$\longrightarrow\rm{S=\dfrac{d+d'}{t_{1}+t_{2}}}$

$\longrightarrow\rm{S=\dfrac{40+60}{1+1}}$

$\longrightarrow\rm{S=\dfrac{100}{2}}$

$\longrightarrow\rm\green{S=50\ km/h}$

Hence, the average speed of car is 50 km/h.