Question

The resultant of the force(-4i+8j)N and the force F gives an object of mass 6kg an acceleration of (2i+3j)m/s^2. Calculate the angle between F and the unit vector j.

Answer 1

F=ma
Since 6a = 12i+18j
and F•a = |F|*|a| cosθ
you can now find cosθ, and hence θ

Answer 2

16i+10j

Answer 3

(-16i -8j)

Answer 4

73.9