Question

A boy has to go 500 m due north, 400 m due east and 200 m due south to reach his school. He
takes 20 minutes to reach the school. average velocity of boy during the walk is X/12 m/s . find the value of x
​

Answer 1

Answer:

5

Explanation:

figure:

             400m

           ---------------

           |              |

500m  |--------------| 200 m

           |

by joining the starting and ending points we get a right angled triangle

the measure of sides forming the right angled triangle is 400m and 500-200 = 300m

By Pythagoras theorem,

hypotenuse^{2} = 300^{2} + 400^{2}

= 90000 + 160000

hypotenuse^{2} = 250000

hypotenuse = 500m

since its the minimum distance between the house and school,

displacement = 500m

time taken = 20 minutes = 20(60) seconds = 1200 seconds

velocity = displacement/time

x/12 = 500 / 1200

x/12 = 5 / 12

x = 5 × 12/12

x = 5