Question

A submarine emits a sonar pulses which returns from an underwater cliff in 1.02sec , if the speed of the sound in salt water is 1531m/sec, how far away is the cliff?

Answer 1

A submarine emits a sonar pulses which returns from an underwater cliff in 1.02 sec , if the speed of the sound in salt water is 1531m/sec.

We have to find the distance of the cliff.

Let us assume that the cliff is 'x' m away from the submarine.

A submarine emits a sonar pulses which is going to the underwater cliff and coming back. Distance from submarine to cliff is 'x' and again it coming back through the same pathway. So, again the distance covered is 'x'.

Total distance covered = x + x = 2x

Given speed of sound in salt water is 1531 m/s and time is 1.02 sec.

Now,Distance = Speed × Time

Substitute the known values

→ 2x = 1531 × 1.02

→ 2x = 1561.62

Divide by 2 on both sides,

→ 2x/2 = 1561.62/2

→ x = 780.81

→ x = 781 (approx.)

Therefore, the cliff is 781 m away.

Answer 2

GiVeN :-

Time, t = 1.02 s

Speed of the sound in salt water, v = 1531 m/s

To FiNd :-

The distance of the cliff from the submarine.

SoLuTiOn :-

The sonar travels from the submarine to the cliff, and again returns back to the submarine by reflection of sound. If we assume the distance between the submarine and the cliff to be s km, then the total distance covered will be s + s = 2s km.

We know,

$\boxed{\sf{\dag\ Distance\ travelled=Speed \times Time\ taken }}$

Substituting the values :--

2s = 1531 × 1.02

⇒2s = 1561.62

⇒s = 1561.62/2

⇒s = 780.81 m

Therefore, the cliff is 780.81 m away from the submarine.