Forces on an object, Force vector

[Rileyss123]

There are two forces on the 1.1 kg box in the overhead view of Fig. 5-37 but only one is shown. The figure also shows the acceleration of the box.

IMAGE : http://www.webassign.net/hrw/05_37.gif

(a) Find the second force in unit-vector notation.
N i + N j

(b) Find the second force as a magnitude and direction.
N,
° (counterclockwise from the +x-axis is positive)

I'm not exactly sure where to start. Using F=ma then F= (1.1)(12)=13.2
so is the net Force 13.2
and for N in part be would the answer be either 20tan(30) or 20/tan(30) ??

 

[ritwik06]

There are two forces on the 1.1 kg box in the overhead view of Fig. 5-37 but only one is shown. The figure also shows the acceleration of the box.

IMAGE : http://www.webassign.net/hrw/05_37.gif

(a) Find the second force in unit-vector notation.
N i + N j

(b) Find the second force as a magnitude and direction.
N,
° (counterclockwise from the +x-axis is positive)

I'm not exactly sure where to start. Using F=ma then F= (1.1)(12)=13.2
so is the net Force 13.2
and for N in part be would the answer be either 20tan(30) or 20/tan(30) ??

You are asked to find the second force and not the net force.
As you have calculated the net force and you know its direction, resolve it into components
F(net)= -13.2 sin 30 i + -13.2 cos 30 j
F1= 20 i
F1+F2=F(net)

Find F2 now