Two friends are standing along a steel fence at a distance of 340 m from each other. Class 9

Two friends are standing along a steel fence at a distance of 340 m from each other. Class 9

Question 1.

Two friends are standing along a steel fence at a distance of 340 m from each other. Gunjan places her ear over the fence and her friend knocks the fence with a metal object. Using the values of the speed of sound in steel and air given in Table -1, calculate the time difference between the sound that reached Gunjan through the air and the steel. Would it have been possible for her to distinguish between the two sounds? (The time interval between two sounds must be at least 0.1 s to be heard separately.) (Page 198) Class 9

Answer:

Distance = 340 m

Time taken through steel = distance / speed in steel = 340 / 5000 = 0.068 s

Time taken through air = distance / speed in air = 340/340 = 1.0 s

Time difference = 1.0 - 0.068 = 0.932 s

Since 0.932 s > 0.1 s, Gunjan would be able to distinguish between the two sounds.