I WILL MARK YOU AS BRAINLIEST IF RIGHT In order to climb up a mountainside, a train needs to start at a speed of 40 mph. The speed limit on the track, however, is 25 mph. How much time does the train need to get up to 40 mph if it can accelerate 4 mph per minute ?

Let's see what to do buddy.....

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Thus ;

The speed increases 4 units per minute.

The train has a speed of 25 mph now.

After a minute it has a speed of 29 mph.

After a minute it has a speed of 33 mph.

After a minute it has a speed of 37 mph.

Look ; 4 units per minute means 4 units per 60 seconds, thus the speed increases 1 unit per 15 seconds .

If the speed wants to increasing from 37 to 40 , needs 3 × 15 seconds = 45 sec.

So we have : 1 min + 1 min + 1 min + 45 sec .

3 minutes and 45 seconds or 225 seconds need to the speed increasing from 25 mph to 40 mph.

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And we're done.....♥️♥️♥️♥️♥️

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me