Vector Kinematics Bonus Question

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1. Feb 24, 2016

Asleky

1. The problem statement, all variables and given/known data
A plane went 300m/s 35° south of west then 230m/s 20° east of north. What is the magnitude and direction of the 65kg pilot during the 12s turn?

2. Relevant equations
Kinematics. Vf = Vi + at, d = ViT + 0.5at^2, Vf^2 = Vi^2 + 2ad

3. The attempt at a solution
This was a question on my Physics C exam in January. Sorry, the question wording is terrible because it's from my memory as well, and I don't have any work to show. That's why all I'm asking is for a very general outline of HOW to solve this because I am at a loss. During the exam I tried to convert each vector into x and y components but I wasn't sure what to do then. I would probably use kinematics equations to solve for...whatever magnitude is, then use trig to find the direction. I'm sorry the question couldn't be more specific. :( Thanks for any hint!

2. Feb 24, 2016

Orodruin

Staff Emeritus
The pilot does not have a direction. The question was likely asking for the magnitude and direction of the mean acceleration or force during the turn. How would you find that out?

3. Feb 24, 2016

Asleky

I would use change in velocity / change in time in both the x and y directions to find acceleration in x and y. F = ma, so use the acceleration and mass of the pilot to find the x and y forces and then use Pythagoras to find total force? :D

4. Feb 24, 2016

Orodruin

Staff Emeritus
You can do it like that, but in this particular case I think it would be easier to just draw a velocity triangle and use the cosine and sine theorems to find out the magnitude and direction of the velocity change. Both methodsshould of course give the same answer.