Posted by Hannah on .
A force, F1 of magnitude 2.0N and directed due east is exerted on an object is F2=2.0N due north. What is the magnitude and direction of a third force, F3, which must be exerted on the object so that the resultant force is zero?
I am not sure how to start this problem!! Thank you for your help!

Physics(Please help) 
Elena,
Net force F12 is the vector sum of F1 and F2. Its magnitude is
F12 =sqrt(F1² + F2²) = 2√2 = 2.82 N.
It is directed along the diagonal of the square which sides are vectors F1 and F2. F3 has to be directed opposite to the F12 and has to be equaled to F12. 
Physics(Please help) 
Hannah,
thank you!

Physics(Please help) 
Liza,
Can i get a draw for this exercise cause i solved it but i cant see it Thanxsz

Physics(Please help) 
Mduduzi Thomas,
Run 6km in a southerly direction after turns and runs 9km due north. The total time for the race is 5hours. The runners average speed in m.s