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# Relative Velocity – Flight JS296

(11)
Tuition given in the topic of A-Maths Tuition Questions from the desk of at 12:17 pm (Singapore time)

Updated on

No. She’s not the Head Stewardess
of Flight JS296.

Dear passengers, welcome aboard Jφss Sticks Airways flight JS296 bound for Bangkok. This is your Head Stewardess Miss Loi speaking.

Unfortunately, due to … umm … some wild party in the cockpit last night (damn those pilots!), our Captain has been completely knocked out and has now handed over the reins of this aircraft to yours truly!

But yours truly doesn’t know the way! These are his last instructions before he passed out:

Our flight is scheduled to fly due north from Singapore to Bangkok. Bangkok is 1400 km from Singapore. There is a wind blowing from the bearing 060o at a constant speed of 96 km/h. Given that the speed of the plane in still air is 800 km/h, find

1. the course that needs to be set by the pilot.
2. the flight time, to the nearest minute.

On the return journey, the wind will be flowing at the same speed from the bearing 030o and the speed of the plane in still air remains unchanged, find

1. the course that needs to be set by the pilot.
2. the flight time, to the nearest minute.

Now please turn to the last page of your Passenger Safety Handbook and look at the para titled Relative Velocity.

*moans of utter dismay from passengers*

Please don’t panic, everyone. Being a full-time tutor (yes just standing-in for the Head Stewardess for this flight), I understand that Relative Velocity is a daunting topic for most of you.

Tales of rivers, ships, planes, flies, spiders, or whatever that moves aside, they can be generally solved using trigonometry or vectors.

But no matter the type, you’ll need to remember this till the end of days:

vp = vp/w + vw

where,
vp = resultant velocity of p
vp/w = velocity of p relative to w (usually described as ‘in still air/water etc.)
vw = velocity of w (usually wind, water etc.)

Now, dear passengers, since we’re short of time (else MBK will be closed by the time we get there!), our chances of shopping in Bangkok today will depend greatly on your trigonometry skills, especially your sin and cosine rules!

Last but not least, check your bearings! Please, please know the difference between various words like to, from, due and of course your North-South-East-West!

So can anyone help poor Miss Loi get everyone safely to Bangkok, and back (knowing the Captain, think he will miss his flight again for extending his Thai massage session – duh!!!)?

Thank you for your kind attention. Miss Loi shall now address our Thai passengers.

### Revision Exercise

To show that you have understood what Miss Loi just taught you from the centre, you must:

1. Janice commented in tuition class

2007
Aug
15
Wed
12:34pm

1

Nice blog. Love your little humour in the post 🙂

2. WishBoNe commented in tuition class

2007
Aug
15
Wed
1:02pm

2

I forogt how to do velocity. 😛 And the captain is lousy. How can pass out just like that?

3. Miss Loi Friend Miss Loi on Facebook @MissLoi commented in tuition class

2007
Aug
15
Wed
3:35pm

3

Janice, thanks for your kind words but this is a grave matter! The Bangkok sale is ending tonight!

4. Miss Loi Friend Miss Loi on Facebook @MissLoi commented in tuition class

2007
Aug
15
Wed
3:42pm

4

WishBoNe, maybe the Captain himself is too stressed by this Relative Velocity question!

5. Becky commented in tuition class

2007
Aug
16
Thu
10:33pm

5

6. Jason Ho commented in tuition class

2007
Aug
17
Fri
12:26am

6

woah..everyone is going to Thailand..but yeah..it is a lovely place isn't it? enjoy yourself and do get hammered..beer is cheap...oh yeah..drool~

7. Miss Loi Friend Miss Loi on Facebook @MissLoi commented in tuition class

2007
Aug
17
Fri
2:51pm

7

Becky, thanks for your flattering words. Your blog theme is neat too.

But a pity you don't have the solution to the problem. Some passengers are already demanding a refund now!

8. Miss Loi Friend Miss Loi on Facebook @MissLoi commented in tuition class

2007
Aug
17
Fri
3:02pm

8

Hello Jason!

Think you've enjoyed your Thailand trip a great deal. Now have naughty Jason been hammering too many nails at the bar? *sly wink*

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