In: Physics
Four forces are acting on an object in static equilibrium: Force 1 has a magnitude of 46.0 N and is acting at an angle of (45 + A) degrees above the positive x-axis. Force 2 has a magnitude of (15+B) N and is acting along the positive x-axis. Force 3 has a magnitude of 34.5 N and is acting along the negative y-axis. Find the magnitude of the last force, F4. Give your answer in newtons (N) and with 3 significant figures
A = 7 B = 13

From given data,  
;
; 
Also given that 
 and 
Resolve the given forces into components

i) Horizontal component is

  
ii) Vertical component is
  
  

i) horizontal component is


ii) vertical component is
  

i) Horizontal component is 
ii) Vertical component is 
Let us consider the horizontal and vertical components of force-4 as shown in the figure.
Thus at equilibrium,
i)Algebraic sum of horizontal component of forces is zero. That
is 


ii) Algebraic sum of vertical components of forces is zero. That
is 


Therefore, the magnitude of force F-4 is given by

  
  
Thus, the magnitude of force F-4 is