Question

A submarine moved from the water surface at a speed of -20meter per minute. How far is the submarine from the water surface at the end of 7 minutes?

Answer 1

Question :

A submarine moved from the water surface at a speed of 20 m/min . How far is the submarine from the water surface at the end of 7 minutes?

Given :

• Speed of Submarine = 20 m/min
• Time interval (t) = 7 mins

To Find :

• How far is the submarine from water surface in end of 7 minutes.

Solution :

We're given that the speed of Submarine is 20 m/min, we've to convert it to the SI unit which is m/s by multiplying it by 1/60.

⇒Speed = 20 m/min

⇒Speed = 20*(1/60)

⇒Speed = 20/60

⇒Speed = 1/3

⇒Speed = 0.333

➠ Speed is 0.33 m/s

_________________________________

Also, we've to change time in seconds. So, multiply it by 60

⇒Time = 7 mins

⇒Time = 7 * 60

⇒Time = 420

➠ Time is 420 seconds

________________________________

Distance travelled by submarine is :

⇒Speed = Distance/Time

⇒Distance = Speed * time

⇒Distance = 420 * 0.33

⇒Distance = 138.6

$\therefore$ Distance travelled by submarine is 138.6 m (approx)

Answer 2

Given :

• A submarine moved from the water surface at a speed of -20meter per minute.

To Find :

We have to find that How far will the submarine from the water surface at the end of 7 minutes ?

Solution :

If the speed of the submarine is (-20) per minute then it states thet submarine is going 20 m below in every minute.

So,

⇒ Distance = Speed * Time

→ Distance = 7 * (-20)

→ Distance = -140 m

∴ Since, the submarine is below sea.

So, distance travelled by submarine is 140 m.