EM 306 – Statics

The University of Texas at Austin
EM 306 – Statics
Exam #2, Spring 2010
Time: 7:00 – 9:00 pm, Tuesday, April 20
Place: WEL 2.246
Unique number (circle one):
Closed books, notes, and homework.
1. See figure below. A beam AB is simply supported and subjected to a concentrated force P at
the mid-span and a distributed load of intensity q over one-half of the span. Neglect the
weight of the beam.
(a) Find the reactions at A and B. (10)
(b) Find the internal shear force and bending moment at a section of distance 20 inch to the
left of B. (15)
(c) Draw the shear force and bending moment diagrams for the entire beam AB. Mark the
maximum bending moment and its location. (10)
2. Determine the range of mass m for which the 100-kg block is in static equilibrium. Neglect the
mass of the pulley.
(a) Assume all wheels and pulleys have negligible friction. (15)
(b) Determine the range when the coefficient of static friction between the belt and the pulleys
is 0.1. Assume that both pulleys do not rotate. (10)
Hint: For part b, use the formula for belt friction: ܶଶ ൌ ܶଵ ݁ ఓఉ .
3. See figure below. The 200-kg slider A is held in place on the smooth vertical bar by the cable
(a) Find the magnitude and direction of the force in the cable. (15)
(b) Find the magnitude and direction of the contact force between the slider and the vertical
bar. (10)
(c) Find the moment about O due to the force in the cable exerted on the hook at B. (15)