Kinematics 2-D Help, please

[Kandi]

I'm really stuck on this physics problem:

 

A plane is flying at 130 mph, on a course S 20 E. The wind is blowing 30 mph due east. What is the final speed and direction?

 

I know to begin with finding the plane in mph going North and East, but I'm confused on whether to use sin,cos, or tan. I'm also stuck on what to do next after that? It would be much appreciated if anyone could please explain what steps to take. Thanks!!

[timo]

Sounds like a stupid question to me. If the plane is flying 130m/h on a course S 20 E (whatever this direction means) then it´s most certainly flying 130m/h on a course S 20 E.

 

What you are probably supposed to do is to rewrite 130m/h on a course S 20 E as a vector, add up the windspeed and rewrite it as {magnitude, direction}. But strictly speaking that´s not what is asked for.

 

If I were you I´d answer "130 mph, on a course S 20 E" because that shows that you can think beyond dumb "we just learned using vectors so I misinterpret the question to become a vector addition". But then, I was never known to be the kind of pupil a math or physics teacher wanted to have in his/her class.

[Karnage]

i could help you out but i need clarification on the "S 20 E" part. I am pretty good at all the three branches of science (more biology/biochemistry though)

[Kandi]

It's meant to read "South 20 degrees East."

[swansont]

Though I think Atheist has a point, I believe the given heading is supposed to be where the plane is aiming, and the wind adds a velocity that does not actually re-orient the plane.

 

Use vector addition of the velocities, as Atheist penultimately suggested.

[Dudde]

thanks for your input on the subject at hand atheist, but next time we can do without the name calling and implications, they're not necessary

[timo]

What name calling exactly? "Stupid question"? I do think the question is stupid and I gave an explanation why I think so. Do you think the question will be offended?

[Phi for All]

I do think the question is stupid and I gave an explanation why I think so. Do you think the question will be offended?

Since you started with:

Sounds like a stupid question to me. If the plane is flying 130m/h on a course S 20 E (whatever this direction means) then it´s most certainly flying 130m/h on a course S 20 E.

then it could be interpreted as, "Kandi, what a stupid question you are asking!" We now understand that you think the question from the teacher is stupid, not the question from Kandi.

 

The staff is perhaps overly sensitive about insults here at SFN, but we love our members and want them to feel good about being here and comfortable about asking anything.

[timo]

It was certainly not meant as a "Kandi, what a stupid question you are asking!". But I am pretty convinced that this should be obvious if one read my whole post which I´d expect from Kandi (since it´s "his thread" so he should be interested in the replies) and especially from Dudde (since he felt competent enough to comment on my post).

 

I probably should have had used a formulation like "stupid exercise" to avoid an ambiguity but such ambiguities easily happen in a forum form of conversation. Learning to reread a statement and rethink if it could mean something else than you first thought -especially if you haven´t read many posts of the person in question before- imho is a social skill that you can learn very well in internet forums.

[Dudde]

because that shows that you can think beyond dumb

 

nevertheless, your response offended someone, please refrain from using comments that may sound insulting to anyone, question or otherwise

 

thank you

[timo]

I skipped the part of my post that complained about your nonspecific generalized statements Dudde (it was within the context of forum comunications - I should have let it in, I think).

Whom exactly did I insult? Are you seriously telling me "do not insult exercises"? Would you be very surprised if I found your recent post a bit absurd?

I was actually expecting an apology from you for not reading my post properly before you blamed me for insulting others. However, the kind of attitude/behaviour you show in your last post does not really give much hope to come to that level. I can live with that. If you feel the urgent need to discuss with me about this matter any further you are welcome to write me a private message.

[Dudde]

I did read the entire post

pm sent