1. Free Body diagrams and problem solving
MYIB / HONORS PHYSICS

2. Free Body Diagrams
A pictorial representation of forces acting on an object complete with labels.
Consider the box being pulled to the right by a rope across the floor

3. TWO types of Friction

4. 3 Common Forms of Friction

5. Sliding Friction
Sliding Friction
Depends on Two Things: 1. 2.

6. Rolling Friction Fluid Friction
Depends on Three Things: 1. 2. 3.

7. Example 1
A 10-kg box is being pulled across the table to the right at a constant speed with a force of 50N.
Calculate the Force of Friction
Calculate the Force Normal

8. Example 1 Continued
A 10-kg box is being pulled across the table to the right at a constant speed with a force of 50N.
Calculate the Force of Friction
Calculate the Force Normal mg

9. Example 2
Suppose the same box is now pulled at an angle of 30 degrees above the horizontal.
Calculate the Force of Friction
Calculate the Force Normal

10. Example 2 Continued
Suppose the same box is now pulled at an angle of 30 degrees above the horizontal.
Calculate the Force of Friction
Calculate the Force Normal FN Fa
Fay Ff 30
Fax mg

11. Example 3
A 10-kg box is being pulled across the table to the right by a rope with an applied force of 50N. Calculate the acceleration of the box if a 12 N frictional force acts upon it.

12. Example 4
A crane applies a force of 500N to a 25kg crate as it is raised into the air. What is the acceleration of the crate?

13. Example 5
A 1500 N crate is being pushed across a level floor at a constant speed by a force F of 600 N at an angle of 20° below the horizontal as shown in the figure.
What is the coefficient of kinetic friction between the crate and the floor?