Question

Help!
1) A force of 3N acts at 60 degrees to a force of 5N. Find the magnitude and direction of their resultant, R.
2) A particle which is moving due east at 4ms^-1 changes direction and starts to move due south at 3ms^-1. Find the change in velocity.

Answer 1

1) so just make 2 vectors and add them to get the resultant vector.
so first the 3N vector can be represented in component form as <3*cos(60), 3*sin(60)> and the 5N vector can be seen as <5,0>. To add the vectors simply add the components so resultant vector is < 5+3*cos(60), 3*sin(60)>. To get a 2D vector's magnitude simply use pythag. to get the direction use arctan.
2) honestly this is hard to express. Are you asking for instantaneous change in velocity? or average?

Answer 2

Thanks!
For No.2 I'm assuming the instantaneous change in velocity.