1. Statics

2. Identifying Static Situations
Objects that do not move linearly (translational motion) or rotate (rotational motion) are static

3. Equations

4. Example
40º
A box of mass 10 kg is placed 2 m from the left end of a 7 m long horizontal beam. The beam has a mass of 20 kg and is supported by a cable that makes a 40º angle to the beam. What is the tension in the cable?

5. Fy F T
40º Fx
98 N
196 N

6. Ladder R Ff Mg FN mg Ff

7. Ladder Problem
A 20 m ladder (mass of 15 kg) is leaning against a frictionless wall and makes a 60 degree angle to the horizontal. What is the minimum coefficient of friction needed between the floor and the ladder to keep the ladder from slipping?

8. R FN mg Ff

9. R θ
90-θ mg θ B