Balance a Loaded Beam on Two Supports
Move the supports and load. The reaction forces update automatically so that both translational and rotational equilibrium can be checked.
Reaction at A350 N
Reaction at B350 N
Total downward load700 N
ΣFᵧ0.00 N
Στ about A0.00 N·m
Beam setup
Measured from the left end.
Measured from the left end.
Drag the load anywhere along the beam.
Downward concentrated force.
Uniform beam weight acts at the beam center.
ΣFy = 0:
RA + RB = P + W
ΣτA = 0: RB(xB-xA) = P(xP-xA) + W(3-xA)
ΣτA = 0: RB(xB-xA) = P(xP-xA) + W(3-xA)
Balanced beam:
The upward reactions equal the total downward load, and the clockwise and counterclockwise moments cancel.
Free-body diagram
reaction Rₐ
reaction Rᵦ
point load P
beam weight W
Vertical-force check
Rₐ + Rᵦ − P − W = 0.00 N
Moment check about A
Στₐ = 0.00 N·m
Predict before moving the load
Move P toward support A. Which reaction increases, and which reaction decreases?