Question

Two forces F1 and F2 with magnitudes 100 Newtons and 120 Newtons, respectively, act on an object at point P as shown in the figure (not to scale). figure and Question attched in comments. I really have no idea how to start, someone pls help.

Answer 1

The magnitude of the first force is F1=| 100[N] |.
The magnitude of the second force is F2= |120[N]|

The direction vector of F1={F}/|F| = {100cos(45)[N] i + 100sin(45)[N] j } / 100[N]
The direction of vector F2 would be the same as F1 but with 120[N] as the magnitude.

So that information should be sufficient for (i)

Part (ii) is asking for the direction of the sum of two forces when they act against each-other.

Part (iii) is asking for the magnitude of the force requested in (ii)

Part (iv) is asking for the angle that the final force makes with a horizontal vector in the <1,0>unit vector direction.

Try it now

Answer 2

thanks, what units will (i) be in ?