9/27 Friction Introduction

1
9/27 Friction Introduction

• Text Chapter 4 section 9 friction
• HW 10/4 Elevator due Wednesday 10/2
• Friction worksheet up front

2
Friction

• Always acts parallel to the surface of contact
• Comes in two flavors static and kinetic
• Static no relative motion of surfaces
• Kinetic relative motion of surfaces (sliding)

3
Friction Worksheet

• Goals
• Conceptualize the difference between Static and
  Kinetic friction
• Discover what each type depends on (tricky as the
  equations for them look identical)
• Typo
• On page 2- The box moves at constant speed
  throughout the page is not true. The first and
  last FBDs are at constant speed.