Question

A train of length 180m approaches a tunnel of length 620m. How long will it take the train to pass completely through the tunnel at a speed of 54 km/h??

Answer 1

Hiya, what are your own thoughts, so far?

Answer 2

180+620/54

Answer 3

Sounds good to me!

Answer 4

really???

Answer 5

The only issue would be your units. You're dividing metres by kilometers per hour, which doesn't sound like a good idea.

Answer 6

Are you doing this as part of maths, or physics?

Answer 7

maths

Answer 8

Great, you need to make sure with these kinds of questions is that your units are consistent. That means it's probably best to work with metres and seconds, so try converting the 54 kilometers per hour into metres per second.

Answer 9

how do you convert from 54 km/h to km/s

Answer 10

Not km/s, but m/s.

Answer 11

54km per hour means 54,000 metres per hour. How many seconds are there in an hour?

Answer 12

3600??

Answer 13

That's right.

Answer 14

So 54 km per hour is the same as 54,000 metres every 3,600 seconds.

Answer 15

Given that, can you work out how many metres every ONE second?

Answer 16

15??

Answer 17

That's right. So the train is travelling at 15 metres every second, that's 15 m/s. Now can you answer your original question?

Answer 18

Remember, as you rightly worked out before, the distance is 180+620=800m. Now that you know the speed as well as the distance, can you work out the time?

Answer 19

so that would be 800/15= 53.3

Answer 20

Sounds good!

Answer 21

HORAAAYYY

Answer 22

Congratulations!

Answer 23

Thank you so much, you will become a legend in no time

Answer 24

Thanks, glad to help!