A ship travelling towards a cliff receives the echo of its whistle after 3.5 seconds. A short while later, it receives the echo after 2.5 seconds. If the speed of sound in air under the prevalling condition is 250ms -1, how much closer is the ship to the cliff?
-
A.
10m -
B.
125m -
C.
175m -
D.
350m -
E.
1,000m
Correct Answer: Option B
Explanation
Difference in time = 1 sec.
echo time = 1 (div) 2 = 0.5 sec.
= 0.5 x 250
= 125m