the distance between a boy and a hill is 250 meters. if the boy shouts after how long will the echo be heard numerical problem​

1.5 s (approx.) and distance of echo traveled is 500m.

Explanation:

As you have not mentioned the speed of sound in the air, let's assume it to be 330 m/s.

Distance = velocity x time

Time = Distance / Velocity

= 250/330

 = 0.75 s (approx.)

This is the time for the sound from the boy to the hill.

An echo is formed from returning the sound from the hill back to the boy.

So, the time for the echo to be heard will be 2 times the time taken by sound from the boy to reach the hill.

So, echo time = 1.5 s

Distance traveled will be 250 + 250 = 500m. We are adding because it is returning back to the boy.

c because the news are a source of information of things that happen on the daily and shows evidence about that particular topic

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.