Question

a car moves with with an average speed of a m/s during first half of its journey ​

Answer 1

Question :

A car moves moves with an average speed of a m/s during the first half of its journey and with b m/s during the remaining half. Calculate the average speed during the entire journey.

Answer :

Let the whole Distance be x m.

Then, first half and the other half Distance will be x/2 m.

Let's find the time.

For the first half Distance -

• Distance = x/2 m
• Speed = a m/s

So, Time = (x/2)/a

⇒ Time = x/2a seconds

For the second half Distance -

Distance = x/2 m

Speed = b m/s

So, Time = (x/2)/b

⇒ Time = x/2b seconds

Now, Average Speed = Total Distance/Total Time.

⇒ Avg. Speed = (x)/(x/2a + x/2b)

⇒ Avg. Speed = [x]/[(xb + xa)/4ab]

⇒ Avg. Speed = [x/1]*[4ab/x(a +b)]

⇒ Avg. Speed = (4ab/a+b) m/s

Hence, Average Speed during the entire journey is (4ab/a+b) m/s.

Answer 2

Answer:

the answer is given....

in 2line it's v avg = s/t1 plus(+)t2