Question

A train travels at the speed of 60 km per hour from station A to station B and then comes back with the speed 80 km per hour from station B to station A find :
1) the average speed second 2)the average velocity of the train ​

Answer 1

Answer:

Explanation:

Let distance from A to B=x\ \ km ==x  km= distance from B to A.

Time taken by train from A to B =\dfrac{x}{60}\ hr=  

60

x

​  

 hr  

Time taken by train  from B to A =\dfrac{x}{80}\ hr=  

80

x

​  

 hr

Total time taken by train =\dfrac{x}{60}+\dfrac{x}{80}=\dfrac{7x}{240}\ hr=  

60

x

​  

+  

80

x

​  

=  

240

7x

​  

 hr

\text{average speed}=\dfrac {\text{total  distance}}{\text{total  time}}=\dfrac{2x}{\dfrac{7x}{240}}=\dfrac{480}{7}\ km\ h^{-1}average speed=  

total  time

total  distance

​  

=  

240

7x

​  

 

2x

​  

=  

7

480

​  

 km h  

−1

Answer 2

${\bold {\boxed{\underline {\huge {\pink {Answer :}}}}}}$

For train A:

speed: 60 km/hr

For train B:

speed: 80km/hr

For average speed

$average \: speed= \frac{total\:distance }{total \: time \: taken}$

$averge \: speed = \frac{60 + 80}{1 + 1}$

$= \frac{140}{2} = 70km$

For average velocity

will be zero

${\bold {\boxed{\underline {\huge {\green {Thanks}}}}}}$