An iceberg is 3,000 metres from a submarine. The submarine emits ultrasound. How long until the submarine detects the iceberg?

3.92s
Ultrasound works by the waves traveling to the object, bouncing off, then returning. So the distance traveled is twice that of the actual distance.
Therefore d=6,000m
d= speed x time
Speed of sound in water is about 1,530.
6000 = 1530 * t
t = 3.92s

Iassume the answer is 75 feet. inwards to outwards rather than outwards to inwards. probably be 75.hachures are stokes drawn in direction of the steepest slope. a series of short parallel lines drawn on a map to indicate topographic relief. it is actually called hachures on contour lines. the small marks in the center of the feature are called hachures.observe the picture attached

Hey did u get the answer?