1. Tutorial 2 MECH 101
Liang Tengfei Office phone : Mobile : Office hour : 14:00-15:00 Fri

2. General Equilibrium Problems
Equilibrium Conditions:
2D:
3D:
Today we will focus on:
How to select the free body?
How to draw the free body diagram?
How to build up equations?

3. Example 1 Determine the reactions at point A and B
Isolate the free body &
use reactions to replace the connections.
Set up equations (resolve, sum) A

4. Example 2 Draw Free Body Diagram (access: # unknow=# equation) Answer:
Ay=183N
Ex=0, Ey=417N, ME=-500N.m

5. Example 3
The wall crane supports a load of 3.5KN. Determine the horizontal and vertical components of the reaction at pins A and D. Also, what is the force in the cable at the winch W? The jib ABC has a weight of 500N and member BD has a weight of 200N. Each member is uniform and has a center of gravity at its center. C E
Answer:
pulley E: T=1.75KN
Member ABC :Ay=35KN Ax=9.966KN
Member DB : Dx=9.116KN Dy=9.216KN
3.5KN

6. Extra question
If A and D are not in the same vertical line, how can we solve this problem?