ME 143 Machine Elements 2
Comprehensive Examination
General Instruction:
Please pass your papers through my email address: jlfgalindo@gmail.com 3 days before the
deadline of submission of grades. First students who will get the correct solution will have better
grades than the succeeding students.
1. Determine the required input torque on the link 2 and the magnitude of the pin forces for
the inverted slider-crank mechanism shown on the figure below starting at Ө2 = 0o and
incrementing it by 10o for a complete revolution. Given L1 = 140 mm, L2 = 85 mm, L4 = 250
mm, and load force F4 = 300 N at an angle of Ф = 48o from link 4 as shown, is the required
torque at each Ө2 clockwise or counter clockwise? Show the results in a table with Ө2 in
the first column.
2. For the 4-bar linkage shown in figure, determine the forces at each of the pins and
the input torque for static equilibrium. The two fixed bearings are 10 in. apart on a
horizontal surface. The input link, link 2, is 5 in. long and currently at 115 o. The
coupler link, link 3, is 15 in. long. The output link, link 4, is 10 in. long. The external
force, Fload, is 40 lbs., is located 5 in. from the fixed bearing, and oriented 70 o
relative to link 4 as shown.
3. Define and discuss the following terms:
a) D’Alembert’s Principle
b) Degrees of Freedom or Mobility
c) Grashof’s Equation
d) Transmission Angle
e) Geneva Mechanism
f) Types of Gears
g) Law of Gearing
h) Planetary Gear System