2. Curved Motion
According to Newton’s first law, if the net force on an object is zero, then the object will remain at rest or will move in a straight line with a constant speed.
For an object to move along a curve, there must be a net force on the object.
One specific case that we will study is motion in a circle with a constant speed, i.e. uniform circular motion.

3. Uniform Circular Motion

4. Newton’s second law for uniform circular motion

5. Example--Figure Skater

6. Example--Gymnastics

7. Example--Roller Coaster

8. Airplane--Vertical Loop

9. Airplane--level turn

10. Circular swing

11. Car rounding a corner on a level road