You and your team are on a reconnaissance mission in a submarine exploring a mysterious object in the cold waters of the Weddell Sea, off the coast of Antarctica. The sonar indicates that the object, which had otherwise been moving erratically, has changed course and is now on a direct collision course with your sub. The captain issues an “all stop” order, bringing the sub to a halt relative to the water. The sonar operator “pings” the object, which amounts to sending a short blast of sound in the direction of the object. The emitted sound wave has a frequency of 1550 Hz and a speed of 1552 m/s (the speed of sound in seawater). The sound reflects from the object and returns 2.582 s after it was emitted from your sub, and its frequency has shifted to 1598 Hz.

(a) How far from the sub was the object when the sound reflected from it?

(b) What is the object’s speed?

(c) How long after you receive the return signal will it take the object to reach your submarine?