Friday, September 14, 2007

A-Math Relative Velocity

R.V is challenging to most, easy for those can see,draw and understand.
I'm going to use this question to reveal the "secret" of doing R.V qn.

An aircraft flies east from A to B, where AB = 400 km. The speed of the aircraft in still air is 600 km/h and velocity of the wind is 80 km/h, blowing from the direction 048O. Find
(a) the course set by the pilot of the aircraft, giving your answer correct to one decimal place;
(b) the time taken for the journey, giving your answer correct to the nearest minute.[6]

Click on the image to view it clearly.

The "secret" is mastering R.V. is in the drawing. You must know where to draw your lines, label your lines, angles.

To order to do this, it's also important to know the terms like speed of plane in still air. Where should the value be placed?



Anonymous said...

Correct me if I'm wrong, but from what I've learnt in school, when the question says "from a direction of 48 degrees" shouldn't the step 2 on your diagram (for Vw) be in the opposite direction? Because for your drawing, it will be blowing "in the direction of 48 degrees".

Anonymous said...

the problem is i cannot even draw the correct one. LOLS

alwaysLovely said...

Anonymous#1: The direction of the wind blowing from 48 degrees as shown in Step 2 is corret.
I've double checked with a current school teacher :)

Anonymous said...

speaking of relative velocity.. our school's teachers aren't going to teach us that topic, as they feel that it's not worth teaching something so confusing for 5 to 7 marks.

will we lose out if it comes out as a compulsory question? ><

alwaysLovely said...

5-7 marks = 3% of the entire papers.
If you are real good with the remaining 97%, do you think you will lose out? :)
You will lose out if you aren't putting in all your best for that 97%.
I believe your school teachers know the best :)
FOCUS on the 97%

Anonymous said...

hello ;D your website is good. but may i know who are you.?
i mean i have never encounter someone like you who really post all o lvl stuff.
but well done [:

alwaysLovely said...

jessica: to find out who me and my fren are, click on our profile.