A submarine uses sonar to detect underwater objects. The sonar emits a pulse that reflects off an object and returns in 0.80 s. The speed of sound in seawater is 1500 m/s. What is the distance from the submarine to the object?

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Question

A submarine uses sonar to detect underwater objects. The sonar emits a pulse that reflects off an object and returns in 0.80 s. The speed of sound in seawater is 1500 m/s. What is the distance from the submarine to the object?

Accepted Answer

600 m — Award 1 mark for correct calculation. Total distance travelled by sound = speed × time = 1500 × 0.80 = 1200 m. Distance to object = 1200 ÷ 2 = 600 m (since the pulse travels to the object and back). B is incorrect — this is the total distance, not the distance to the object. C is incorrect — calculation error. D is incorrect — this doubles the total distance.

Answer

1875 m

Answer

1200 m

Answer

600 m

Answer

2400 m

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