While standing on a sidewalk,you notice that you are halfway between a clock tower and a large building.The clock tower and the building are 170 m apart.When the clock bell strikes the hour,you hear an echo of the bell after hearing it directly from the clock tower.How long after hearing the bell from the clock tower do you hear the echo?
A)0.50 s
B)0.33 s
C)0.25 s
D)0.60 s
E)0.75 s

Question

Quizplus · Accepted Answer

The echo travels the extra distance from you to the building and back to you, which is twice the distance from you to the building. Since you are halfway, this distance is 170 m / 2 = 85 m each way, for a total of 170 m. Sound travels at approximately 340 m/s, so the time for the echo to travel this extra distance is 170 m / 340 m/s = 0.50 s.

While Standing on a Sidewalk,you Notice That You Are Halfway