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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: fredrick on August 12, 2008, 10:06:07 pm

Title: Dynamics
Post by: fredrick on August 12, 2008, 10:06:07 pm: I dont know how to do these type of questions:
[IMG]http://img147.imageshack.us/img147/4218/78443695zd6.png[/img]
[IMG]http://img147.imageshack.us/img147/4218/78443695zd6.7db900bbd9.jpg[/img]
cheers
Title: Re: Dynamics
Post by: mark_alec on August 12, 2008, 10:44:44 pm: Just take each of the force
Title: Re: Dynamics
Post by: Collin Li on August 12, 2008, 10:55:48 pm: Just try to resolve each vector in that direction. Try to draw right-angled triangles to figure out the magnitude of the resolved vectors.

Hint: perpendicular vectors to the desired direction have zero magnitude

Example

in the direction of 8N force:

$= 8 + 10(0) - 11\cos\left(\frac{(115-90)\pi}{180}\right) = 8 - 11\cos\left(\frac{5\pi}{36}\right)$
Title: Re: Dynamics
Post by: /0 on August 12, 2008, 10:59:39 pm: Or take each force, multiply by the cosine of the angle between the force and the direction, and then add all of these products together.
Title: Re: Dynamics
Post by: Mao on August 12, 2008, 11:05:13 pm: here's some very crude sketches:
Title: Re: Dynamics
Post by: fredrick on August 13, 2008, 07:41:14 pm: thanks