Equilibrium

The left end of the beam is the 0 cm mark; the right end is the 100 cm mark. The red support is fixed at the 20 cm mark, and the orange box has a weight of 50 N.

Things to think about:

• For a given situation, do you agree with the values of the support forces?
• The support force provided by the blue support when it is at the 50 cm mark is double what it is when it is at the 80 cm mark. Why is this? (That's true only for this situation, where the red support is at the 20 cm mark.)
• The sum of the two support forces is always equal to what? Must this always be the case?
• If the blue support is moved closer to the center of the beam, what happens to the support forces?
• Can you make the beam tip over? The beam will tip if one of the support forces is negative.

Created by Andrew Duffy, Boston University Physics Department.

Last update October 26, 1998