Question

A road runs mid-way between two parallel rows of building. A motorist moving with a speed of 36 km/ hrs ,sounds horn.
a)find the distance between the two rows of building.
b) When will he hear the echo second time ?
c) Find the velocity of sound in m/sec.

Answer 1

Answer:

Step-by-step explanation:

Velocity of Motor Cyclist - 36 Km/Hr = 10 m/s

He will hear the 1st echo when sound is reflected from point B. Sound will travel from A-B-C. In 1 sec, he will travel 10 m. So AC = 10

Velocity of sound = 330 m/s

In 1 s, sound will travel 330 m = AB + BC

AB² = AF² + BF²

AB  = √(5² + x²)

Similarly, BC = √(5² + x²)

AB + BC = 2 √(5² + x²)

330 = 2 √(5² + x²)

Solving we get,

x = 164.9 m

Distance between 2 buildings = 2 x 164.9

Distance between 2 buildings = 329.8 m

He will hear 2nd echo at E, which is 20 m from A.