Dynamics

[fredrick]

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

[mark_alec]

Just take each of the force

[Collin Li]

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:

[/0]

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.

[Mao]

here's some very crude sketches:

[fredrick]

thanks