Question

An aeroplane flies around a square field ABCD of each side 1000km. It speed along AB is 250 kmalu
BC 600 kmh“', along CD 200 kmh' and along DA 100 kmh! Its average speed over the entire trip
(in kmh-')​

Answer 1

Given:

Side of square field is 1000 km. Speed of plane along AB is 250 km/hr , BC is 600 km/hr , CD is 200 km/hr and DA is 100 km/hr.

To find:

Average speed of the entire trip.

Calculation:

Average speed can be defined as the total distance divided by the total time taken to cover the distance.

$\rm{avg. \: v = \dfrac{total \: distance}{total \: time} }$

$\rm{ = > avg. \: v = \dfrac{1000 \times 4}{total \: time} }$

$\rm{ = > avg. \: v = \dfrac{1000 \times 4}{t1 + t2 + t3 + t4} }$

$\rm{ = > avg. \: v = \dfrac{4000 }{t1 + t2 + t3 + t4} }$

$\rm{ = > avg. \: v = \dfrac{4000 }{ \frac{1000}{250} + \frac{1000}{600} + \frac{1000}{200} + \frac{1000}{100} } }$

$\rm{ = > avg. \: v = \dfrac{4000 }{ 4 + 1.66 + 5 + 10 } }$

$\rm{ = > avg. \: v = \dfrac{4000 }{ 20.66 } }$

$\rm{ = > avg. \: v = 193.61 \: kmph}$

So, final answer is:

$\boxed{ \blue{ \large{ \sf{avg. \: v = 193.61 \: kmph}}}}$