TOPIC: FRICTION AND WEDGES
This module covers determination of the frictional forces acting on a structure.
Specifically, it will focus on the study of dry frictions.
Objective:
This module let the students analyze the internal frictional forces acting on several types
of structures. Only statically determinate structures, which do not have more supporting
constraints to maintain an equilibrium condition will be tackled in this module.
Module Guide:
Each lesson in the module begins with a discussion, followed by examples and ends with
a set of exercises with answers provided. You can also visit the youtube.com for more video
discussions.
Module Outcomes:
1. Understand the principles of static, wedge and belt friction.
Module Requirements:
At the end of this module, the students will submit the following:
1. Provide solution to all the exercises of each lesson.
Learning Plan
TOPIC: Friction
Let’s Hit These:
At the end of this lesson, students should be able to:
✓ Understand friction.
✓ Solve problems involving frictions.
Let’s Get Started: Friction is the contact resistance exerted by one body when the second body moves
or tends to move past the first body. Friction is a retarding force that always acts opposite to the motion
or to the tendency to move.
Types of Friction:
1. Dry friction, also called coulomb friction, occurs when unlubricated surfaces of two solids are in
contact and slide or tend to slide from each other. If lubricant separates these two surfaces, the
friction created is called lubricated friction. This section will deal only with dry friction.
2. Fluid friction occurs when layers of two viscous fluids moves at different velocities. The relative
velocity between layers causes frictional forces between fluid elements, thus, no fluid friction
occurs when there is no relative velocity.
3. Skin friction also called friction drag is a component of the force resisting the motion of a solid
body through a fluid.
4. Internal friction is associated with shear deformation of the solid materials subjected to cyclical
loading. As deformation undergo during loading, internal friction may accompany this
deformation.
In this module we will focus on the study of dry friction.
Take note on how to read your
Greek symbols:
“𝜽” --> theta
“𝝓” --> phi
“µ” --> myu or mu
LEARN MORE ON DRY FRICTION:
SAMPLE PROBLEM 1:
SOLUTION:
SAMPLE PROBLEM 2:
SAMPLE PROBLEM 3:
SAMPLE PROBLEM 3:
❖ ACTIVITY FOR FRICTION:
1. A short video presentation showing personal experiment on friction.
(not less than 1-minute).
Send through this link: https://forms.gle/SuerBLPupBJTX67r5
2. Refer to this link:
https://mathalino.com/reviewer/engineering-mechanics/friction
✓ From Friction problem 506 – 544 from the mathalino site,
choose 25-problems and write your solutions in any size bond paper.
✓ Scan your problems and solutions and send to the same link above.
