# Determine the horizontal and vertical components 2

Determine the horizontal and vertical components of reaction at the pin A and the reaction of the rocker B on the beam.

Image from: Hibbeler, R. C., S. C. Fan, Kai Beng. Yap, and Peter Schiavone. Statics: Mechanics for Engineers. Singapore: Pearson, 2013.

Solution:

Let us first draw a free body diagram showing all the forces affecting the beam. Remember that since the beam is in equilibrium, all forces added must equal 0.

We can first solve for $N_B$ by writing a moment equation at point A.

$\circlearrowleft^+ \Sigma M_A=0;$

$N_B\text{cos}\,(30^0)(8)-4(6)=0$

$N_B=3.464$kN

Now, we can write an equation along the x-axis like so:

$\rightarrow^+\Sigma F_x=0;$

$A_x-3.464\text{sin}\,(30^0)=0$

$A_x=1.732$ kN

Next, we can write another equation along the y-axis:

$\uparrow^+\Sigma F_y=0;$

$A_y+3.464\text{cos}\,(30^0)-4=0$

$A_y=1$ kN

$A_x=1.73$ kN

$A_y=1.00$ kN

$N_B=3.46$kN

## 2 thoughts on “Determine the horizontal and vertical components”

• Ab

why you redirected the angle 30 like that? i don’t understand how the angle become like that. kindly explain

• questionsolutions Post author

It’s a roller at B, which means the force will be perpendicular to the ground, so if you draw it out, you will see that since it’s perpendicular, the angle will be 30 degrees from the y-axis (vertical line).