6-a man standing in a valley between two parallel mountains fires a gun and hears echo at an interval of 2.
3.5s. what is
(a) the distance between two mountains
() the location of the man with respect to the mountain. (speed of sound=334 m/s)

(a) 918.5 m

(b) 334 m from the nearest mountain and 584.5 m from the furthest mountain

Explanation:

Echo is a reflected sound so the time taken is for twice the actual distance

Let the distance between the nearest mountains and man = x m

and the distance between furthest mountains and man = y m

Distance between two mountains = ( x + y ) m

Total distance covered by sound to produce first echo

= 2x m and time = 2 sec

=> 2y = 334 x 2

=> x =(334 x 2)/2 = 334 m

Total distance covered by sound to produce 2nd echo = 2y m and time = 3.5 sec

=> 2y = 334 x x 3.5

=> y = (334 x 3.5)/2 = 584.5 m

So, Distance b/w two clif = ( 334 + 584.5) = 918.5 m

(b)

The location

The man is 334 m from the nearest mountain and 584.5 m from the furthest mountain

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

pecialized keyboards