Engineering Statics


For the beam and loading shown, determine the reaction at point A and the tension in cable BC.

By taking moments about point A, the point through which one of the 
unknowns passes, we are able to write an equation with only one 
unknown in it.  Note that since the beam is in equilibrium, the 
summation of moments is equal to zero.
Since the beam must also be in force equilibrium, we can set the sum of 
forces in the y direction equal to zero.
Solving allows to find the force at A in the y direction.