resolving forces m1 aqa, wrong signes

petr

New member
Joined
Oct 22, 2015
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24
Hello,

I dont know in which drection should i start resolving forces.
Usually i come up wwith correct answer to a problem sometimes i ve got simple result like
F-20sin 15 and it is wrong. in this case it was suposssed to be -F+20sin
the friction goes (f)-> this direction and there is a component force opposing (sin)<-
it is on inclined plane. so i start from the right side positively
f-20 sin 15.
now i notices that the particle travels downwords so that probably the reason why.

but anyway, do you have any particular strategy for solving this sort of stuff?

thank you,
petr.
 
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