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# What are the missing forces on this Free Body Diagram?

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• Newton's first law states that when viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force.
Answer: F$_1$ = 22N (Up) and F$_2$ = 13 N (Left).
According to Newton’s first law, since the object is at rest, the net force must be zero. Choose up as positive. So down is negative.
Consider the forces along the x-axis:
If Net force $= 0 \rightarrow 0 = 28N - 15N - F_2 \rightarrow F_2 = 13N$ (Left)
Consider the forces along the y-axis:
If Net force $= 0 \rightarrow 0 = 22N - F_1\rightarrow F_1 = 22N$ (Up)
edited Aug 19, 2014