6: Applications of Newton’s Laws

*Stock cars racing in the Grand National Divisional race at Iowa Speedway in May, 2015. Cars often reach speeds of 200 mph (320 km/h). (credit: modification of work by Erik Schneider/U.S. Navy)*

Car racing has grown in popularity in recent years. As each car moves in a curved path around the turn, its wheels also spin rapidly. The wheels complete many revolutions while the car makes only part of one (a circular arc). How can we describe the velocities, accelerations, and forces involved? What force keeps a racecar from spinning out, hitting the wall bordering the track? What provides this force? Why is the track banked? We answer all of these questions in this chapter as we expand our consideration of Newton’s laws of motion.

#### 6.1 Solving Problems with Newton’s Laws

- Apply problem-solving techniques to solve for quantities in more complex systems of forces
- Use concepts from kinematics to solve problems using Newton’s laws of motion
- Solve more complex equilibrium problems
- Solve more complex acceleration problems

#### 6.2 Friction

- Describe the general characteristics of friction
- List the various types of friction
- Calculate the magnitude of static and kinetic friction, and use these in problems involving Newton’s laws of motion

#### 6.3 Centripetal Force

- Explain the equation for centripetal acceleration
- Apply Newton’s second law to develop the equation for centripetal force
- Use circular motion concepts in solving problems involving Newton’s laws of motion

#### 6.4 Drag Force and Terminal Speed

- Express the drag force mathematically
- Describe applications of the drag force
- Define terminal velocity
- Determine an object’s terminal velocity given its mass