Friday
March 24, 2017

Post a New Question

Posted by on Saturday, June 9, 2012 at 12:06pm.

The mass of the sign shown is 28.5 kg. Find the weight supported by (a) the left support and (b) the right support.

Between the left and right support is 0.900m and from the right support to the end of the sign is 0.300m.

------------------------------
| | --------> (0.900m)|| --->(0.300m)

I got answers: a. 111.1 and b. 186.2 but I'm not sure if they're correct. Can someone please help?

  • Physics - , Saturday, June 9, 2012 at 6:15pm

    Weight of the sign is W = mg = 28.5kg•9.8m/s² = 297.3N
    The sum the moments around the left bottom of the sign.
    Clockwise moment Mcw = 297.3N • (1.2m/2) = 167.6 N•m
    Counterclockwise moment Mccw = F•0.9m
    That is, the cw rotation of the sign about the left corner is resisted by a support force.
    F = 167.6N•m / 0.9m = 186.2N ← in the right column

    The left support can be determined in a similar fashion, or simply by noting that it must support the remaining vertical force:
    Left F = W - Fr = 297.3N - 186.2N = 111.1N ← left support

  • Physics - , Tuesday, November 4, 2014 at 1:52pm

    28.5x9.80 = 279.3 not 297.3.
    therefore the left support would equal 93.1 not 11.1

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question